3020 7020 9020 cannot use standard 24 pin power supply.

https://forums.evga.com/Adapting-Power-Supply-for-a-Dell-OptiPlex-9020-m2412915.aspx

https://www.moddiy.com/products/Dell-OptiPlex-3020-PSU-Main-Power-24-Pin-to-8-Pin-Adapter-Cable-30cm.html

A 12 inch long 3 fan Dual Slot card IS NOT PHYSICALLY Fitting into ANY 3020 7020 9020 case. ANY Size including tower.

So none of what you want to do will work.

 

Re: I know the PSU will end up being external from the tower. My questions are:

Are both of these able to be done with the right adapters and so forth? Will the video card fit inside the tower?

Do you have a DT or SFF? If you have an MT, then psu upgrade can be installed inside case. 
If you have MT you can uninstall the 3.5” hdd bay cage to allow for full length gpu installation.  The card is 291 mm long. The case is 417 mm deep.  Your hdd/ssd can be installed in 5.25” odd bay via adapter.

Well shucks.

so if I use that adapter that should solve my PSU issue?? like there will be no adverse reactions to the motherboard? (Sorry! my knowledge on any of this is veeeeery small)

For the Video Card: Is the case the only limitation preventing the install? if the side panel were take off to accommodate a larger card, could maybe a 2 fan card fit??

something like this: https://www.newegg.com/gigabyte-geforce-gtx-1650-gv-n1656wf2oc-4gd/p/N82E16814932286?item=N82E16814932286&source=region&nm_mc=knc-googleadwords-pc&cm_mmc=knc-googleadwords-pc-_-pla-_-video+card+-+nvidia-_-N82E16814932286&gclid=CjwKCAjwkun1BRAIEiwA2mJRWY4nf8I7-FejzC5X91mTzW7ev3IdWKpJm8_xJf_hFfz2984prjGYShoC26YQAvD_BwE&gclsrc=aw.ds

Thanks again! This is super helpful!

I still do not know the form factor of your pc.

Re: so if I use that adapter that should solve my PSU issue?? like there will be no adverse reactions to the motherboard? 

No. if you get the correct adapter for this model it will work fine.

Re: For the Video Card: Is the case the only limitation preventing the install? if the side panel were take off to accommodate a larger card, could maybe a 2 fan card fit

for DT or SFF you can try to install a full size card by removing side panel or using a PCIe riser adapter.

that two fan card from GA is 191 mm long.  https://www.gigabyte.com/us/Graphics-Card/GV-N1656WF2OC-4GD/sp#sp 

you can measure the physical room in your case to see if 191 mm card may fit.

The GTX 1060 does have different VRAM available.

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And finally @MonteRon719, and 'hi' btw, what size is your 7020 - MT, DT, SFF, or USFF?

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In 1st post, OP referred to knowing the PSU would have to sit outside the tower.

I'd never mind the RX 5600 XT.  It's too much GPU for the CPU (whether an I7-4770 or I7-4790).

Processor is too weak for this graphic card:

Intel Core i7-4770 (Clock speed at 100%) with AMD Radeon RX 5700 XT (Clock speed at 100%) x1 will produce 32.49% of bottleneck. Everything over 10% is considered as bottleneck.

Processor is too weak for this graphic card:

Intel Core i7-4790 (Clock speed at 100%) with AMD Radeon RX 5700 XT (Clock speed at 100%) x1 will produce 29.73% of bottleneck. Everything over 10% is considered as bottleneck.

And finally:

Intel Core i7-4790K (Clock speed at 120%) with AMD Radeon RX 5700 XT (Clock speed at 100%) x1 will produce 10.43% of bottleneck. Everything over 10% is considered as bottleneck.

Recommended CPU is the 6-core I7-8700.  You'd need a PC that can run it.

Second GPU choice isn't looking too good either:

Processor is too weak for this graphic card:

Intel Core i7-4790 (Clock speed at 100%) with NVIDIA GeForce GTX 1650 (Clock speed at 100%) x4 will produce 39.76% of bottleneck. Everything over 10% is considered as bottleneck.

PC Builds recommends GTX 970, but that 145w card has two 6-pin connectors.

Graphic card and processor will work great together:

Intel Core i7-4790 (Clock speed at 100%) with NVIDIA GeForce GTX 1060 (Clock speed at 100%) x1 will produce only 0.1% of bottleneck.  And it's 0.54% with the I7-4770.  It doesn't get better than that.

The 120w card would still require a PSU upgrade, but it only requires one 6-pin PSU connection.

Redxps630 is the one I learned a way to check for bottleneck from.

Upon further review of my 1st post in thread, I noticed "5600" got changed to "5700."  I doubt the #'s would be that much different.

I could not get PC Builds to revert to RX 5600 XT.  May be they didn't test it or calculate it another way?

Also, the RX 5600 XT requires two 8-pin connectors.

looks like OP has a 7020 SFF. Optiplex 7020 is only offered in MT and SFF. No DT or usff.

this makes gpu upgrade easier.  If you install psu outside case, and leave side panel off, the gpu can actually have a lot of physical room in length and slot width.  The depth of 7020 SFF is 31.20 cm (12.28 inches).  The only limit to card length is front fan and front bezel.  I estimate those two added together to be almost certainly less than 2” or 50 mm. Therefore your max gpu length can be as much as 262 mm.  
p.10/58
https://topics-cdn.dell.com/pdf/optiplex-7020-desktop_owners-manual2_en-us.pdf