What's your budget look like? Because if you don't have much to spend, you're best off just tossing an SSD in as your boot disk. That'll help significantly. After that, I'd grab 32GB of matching RAM(make sure it's DDR4, not DDR5) and try that.
After that, you're basically building a new PC because to significantly upgrade your CPU- which is the next thing you'd want to- you'd need at minimum a new motherboard as well and probably a case since prebuilt cases can have proprietary layouts and be weird.
If you wanna build your own PC, but can't figure out what parts would be good/what you actually need feel free to reply with a budget and your general location- country is good enough- and I can send you a link to a part list. I used to hang out in /r/buildapcforme and I kinda miss it lmao
If the most resource intensive thing you're looking at is BG3 @ 1080p/60fps, you definitely won't need to spend a few grand.
Here's a link to a build, I'd suggest buying the SSD in that list, and replacing your hybrid drive. You can keep the hybrid as a spare, if you want, but you don't have to. If that solves your issue and gets you the performance you want, cool.
If it doesn't solve your issues, you can just buy the rest of the parts in the list and build a new PC. It's a PCPartPicker link for the UK, so it'll tell you the best places you can order each part in your country. Alternatively, you can buy a prebuilt- probably wanna aim for $1000 USD or so for a prebuilt. I can't really help you with that, not my thing.
If you do end up building your own there's an extremely helpful very long Linus Tech Tips video that breaks down how to assemble the whole thing.