How much can I do to a flat with 20k??

Hi!! Me nd my bf r currently house hunting for a 2 bed flat in the north east of England. We have saved 20k for decorating things and furniture and all the stuff to make a flat nice basically. I was wanting to ask in here bcs im finding it difficult to get an idea of what is realistic for what we could do with a flat. I’ve been looking at booking a viewing for one where the living room, bedroom, hallway and spare room r all really good- just need painting, wallpapering for hallway, maybe putting up a picture rail and then fitting a cast iron fire place in the living room (I think we could diy tho bcs it doesn’t need to work). However the kitchen and bathroom r well ugly- really not my taste at all nd the thought of the kitchen and bathroom needing some work makes me nervous.

For the kitchen I’d replace the counter tops, oven and flooring and we want to retile the backsplash ourselves and change the cabinet handles.
For the bathroom we’d need to replace the electric shower with a mixer (it has a combi boiler), retile it with nice tiles bcs I want a nice retro vibe bathroom and add a shower screen bcs it has a curtain and maybe change the sink to a really nice one.
And I’d love to change the doors to original wooden ones and would looooove to change the front door but idk if that’s realistic.

I hope this post doesn’t come across as me being an idiot lol and I have been googling stuff but I just can’t seem to get a decent picture of what things really cost?? I have no idea😵‍💫😵‍💫😵‍💫😵‍💫 I’m just scared of buying somewhere and then not having the money to make it nice and being stuck in an ugly house bcs I take a lot of pride in what my house looks like!! We’ve already lived in a rented flat before so have quite a decent amount of furniture already but would need to do like sofa, mattress, curtains all that stuff
Thank you so so much if anyone helps much appreciated!! Xoxox