Hello,
I have the same problems as you and I mean exactly the same! Random crashes after sleep mode, BT keyboard / mouse problems. Lately a new problem that has already occurred 5/6 times. My configuration consist in an External dual monitor 27 "and external mouse and keyboard. Everything is connected to an original Dell docking. First, the keyboard and mouse disconnect from the Docking. At that point, only the laptop keyboard and padmouse remain functional. It is therefore instinctive to unplug the dockig station and then plug it back in, but as soon as it is unplugged, the computer goes into Bluescreen. I'm using this WS as a CAD designer in a big industry. I'm starting to think my old HP Zbook was better .... The system administrator updated my BIOS and Nvidia drivers today. Fingers crossed ... (marco from Italy)

Hey, 

Do you also face an issue where the laptop wakes up randomly and goes back to sleep multiple times when it should be on sleep mode? The screens connected to the docking station would turn on randomly to the login screen and turn off many times at night.

Sorry to disappoint buy updating drivers won't solve the bluetooth delay issue. Only a BIOS update from Dell will solve it in the future (if they ever release it).

As for the crashing issues. I'm in contact with @DELL-Cares and trying to troubleshoot and supply them with more information so they can report back to Dell engineers.

In my opinion, all those issues boil down to bad configuration of power management for newer Dell laptops which weren't tested enough with modern standby. The new generation of Dell laptops are unfortunately unreliable.

I will update here if those issues are resolved.

The issue hasn't been solved yet.

All solutions provided by @DELL-Cares didn't have an effect. Including a clean Windows installation.

I have said it once and will say it again, the newer Dell laptops lineup are not configured to work properly with Modern Standby (S0). These laptops often crash on sleep mode, wake up randomly, have issues with bluetooth (also related to power management). I am saddened to see I spent a 4500$ on a high end laptop to find out it has not been tested enough to work with today's standards. 

I have found a workaround presented by @Mgzlcu who is having the same issue as me:

https://www.dell.com/community/Inspiron/Inspiron-15-7510-with-Windows-10-20H2-crashes-during-standby/m-p/8036420/highlight/true#M127859

"

In the meantime I have found that disabling completely "Modern Standby" is a workaround for my Windows10 20H2 version.

To do that you have simply to open the PowerShell and send the following command and then reboot the PC.

reg add HKLM\System\CurrentControlSet\Control\Power /v PlatformAoAcOverride /t REG_DWORD /d 0

 See Microsoft Docs for reference and note that you can check which power mode are supported and enabled using the command.

powercfg /a

Anyway as I wrote this is a workaround and not a solution indeed this enable S3 standby that is considered legacy standby while "Modern standby" should work properly on new systems (See for reference Modern Standby vs S3 ). Moreover even though I am now 99.99% sure that "Modern standby" triggers the issue I am still not sure if the issue is software (OS or driver) or hardware."

I have implemented this workaround and turned off modern standby:

I will test and see if the crashing still occur.

This workaround is not a fix but could prove the issue is caused by modern standby (S3).

Update:

As expected, after performing this workaround which completely disables Modern Standby, the laptop stopped waking up randomly from sleep mode and haven't experienced a crash yet.

This proves the root cause of the issue is related to Modern Standby (S0) which needs to be addressed by Dell.

I'm saddened to update BIOS update 1.7.2 (07 Mar 2022) hasn't resolved the crashing issue and random wakeups on sleep mode. Very disappointing.

Despite supplying Dell engineers with crashing and .dmp files, they have not been able to spot the root cause of the issue. 

The last suggestion from them was to install an SSD firmware (a solution which was already suggested 3 weeks ago and didn't have any effect). It just shows they are very far away from solving the crashing issues affecting all new Dell laptop lineup.

Dell is suggesting to replace the SSD and Motherboard (I doubt it will solve the issue and I'm extremely afraid for more issues after a technician replaces  the internals). Moreover, Dell wants me to install the OS myself after the parts has been replaced because "on-site technicians are only trained to replace parts" which is ridiculous. 

I canceled the on-site parts replacement as I'm certain it's a software issue and would rather continue using my work-arounds like disabling modern standby or disabling the finger-print reader device.
This has been an ongoing issue for over a year for many users so I don't see any convincing reason to replace parts. The only thing that needs to be done here is to start firing engineers.
Just search "BSOD sleep" or "Modern Standby", "black screen", "random wake up", "bluetooth lagg" and you will see horror stories.
I would advice to stay away from the new Dell lineup that supports Modern Standby (S0).
Modern Standby is extremely dangerous and could make a laptop randomly wake up in a case. Microsoft pushed for this to make laptops wake up faster and perform background operations just like smartphones. On the other hand, Dell warns from encasing the laptop while on that state. It doesn't make any sense to me, why embrace such a faulty standard. Expect a lot of complaints from hundreds of customers.

Update:

I have found a workaround suggesting to disable c-states control as shown in this thread:

https://www.dell.com/community/XPS/Dell-XPS-15-9500-crashes-when-leaving-sleep-or-hibernation-mode/m...

The laptop hasn't crashed for 2 days after implementing this. I will keep testing and updating. I'd also appreciate it if other affected users to try this workaround and test with me.

Dell engineers are trying to find the root cause of this issue. Will keep you posted here.