I've been using a board I bought back in 2014 with a DX11 card and haven't really made an attempt to upgrade these for a while.
The performance is fine but with newer games actually using DX12 software Im starting to run into problems

Is it OK to use a newer card on an old mobo or do I just need to update the bios with latest drivers so it works?

if your gpu isnt dx12
u arent running dx12

2014 mobo arent that old,
so u can use new gpu with it

make sure u remove ur previous gpu drivers completely and dl/install the latest updated drivers for ur new gpu

Plus you need Windows 10 for dx 12


Side note no card out there fully supports dx12 yet

dx12 bandwagon is an early hoppin bandwagon at the moment. better hardware will arise when it actually matters.

Questions:

Gpu model?
Also, maybe a whole system spec would be good.

We could help u choose a new gpu if ure struggling

Fact: Dx12 is gpu limited, so we need to know the model.
Win10 is obligatory.

The win10 parts answered my question.
I will just keep chugging with what i've got then

Tried w10 already but my older games are no longer compatible like they were with w7

Which games haven't ran into any issues myself
Actually i am able to run software in win 10 that couldn't on 7 or 8 without xpmode, tweaks, and fixes

Older dos games like kings quest and wc2
I can get wc2 to work with some tweaks but really old w95/dos games are straight up hard to work with
Doesn't work on w10