Replacement motherboards

I'm not sure we can really help you select a retail (after-market) motherboard to be retro-fitted into an old Dell XPS computer. However, if someone can, they will post and try to help you.

I can say what you propose is not as easy as it sounds, as some Dell parts/cases are fairly proprietary. It's usually easier to just pickup a retail (after-market) case (and maybe even a nice power-supply) while you are shopping.

Lets start here ... what exact model XPS desktop computer do you have?

And are you sure you want to try a custom-build this time and not another pre-built one?

If all of your old hardware is compatible with your new motherboard, then yes, you can do a 1:1 swap. More often than not, you should plan to buy and install new hardware in addition to your motherboard.

I am going to guess it's XPS 8700.  And no, a motherboard replacement is not the best option to move to Win 11.  It will required replacement of CPU, RAM and a great amount of effort to mod everything to fit in that case.

A new(er) PC will be cheaper and better option for Win 11.  If budget is a concern, you can test install Win 11 on your current machine with a new drive.  Be sure to remove all your current drives as backup if you want to revert back.  You can make a Windows 11 installation USB using Rufus with option for unsupported machines. 

If you have an 8700, it can't run W11, and I would not expect any Dell model motherboard to fit into the 8700 case? That is slip in an 89xx board that has the TPM chip W11 requires.

I'd think a new case. power supply, motherboard (W11 capable) and  a new CPU and then salvage the other components you now have. Drives, RAM, etc.

Re: after looking at supported CPUs and the specs of the current one (Intel(R) Core(TM) i3-4150 CPU @ 3.50GHz 3.50 GHz), it seems like a replacement of the motherboard would seem to be the best option if I want to keep the tower. What would be the best motherboard replacement for this model can run Windows 11?

If amenities of new chipset features (M.2 ssd) or >= 6 core cpu is not top OP concern, why not just upgrade cpu from dual core i3-4150 to quad core i5-4570 or i7-4770/4790 on the stock motherboard, then install Windows 11 on it using cpu/tpm/secure boot bypass installation media?  I installed Win 11 on similar Dell intel 4th gen desktop platform (optiplex 9020) without glitch and pc runs fine.

otoh, a good modern oem microATX mobo upgrade for XPS 8700 would include Z370 chipset such as that of XPS8930 or Aurora R8/R9 paired with i5-8400 or i7-8700.  This would however need user modding of Dell usb header or led controller.  A direct drop in Z370 mobo to replace XPS 8700 would include microATX from non-Dell maker such as this one.  https://www.amazon.com/EVGA-Micro-Intel-Motherboard-121-KS-E375-KR/dp/B077P42J3N