Brought house with partner 24.11.23, trashed garden in the summer, now we've separated. How screwed am I?

I brought my house back on November 2023. Everything was perfect, no decorating was needed, garden looked perfect, couldnt ask for more.

Found out pretty quickly the decking was rotten and needed ripping up. So I got to work and threw all the wood onto grass. What I didn't realise was, it was going to pretty much rain solid for the next several weeks so the grass ended up dying out.

Fast forward to now. The patio and side entry is slabbed in indian sandstone. The grass coverage is about 60%, there's a 3ft wide pile of gravel in the middle off my grass which needs topsoil and reseeding, a forest size worth of uncut logs for logburner and a skips worth of garden waste at the side of my patio area. I'm hoping to have it all complete by the end of this summer.

Inside the house was immaculate when we moved in, white walls, oak flooring, butchers block work surface in the kitchen, 12 months later and 2 kids under 3, there's food stains on the walls from when they decide they no longer want to eat and launch the plate into the floor, there's stains on the work surface from God knows what. It's all things that can be fixed cheaply and quickly but this is where my problem comes in.

She's decided she wants to split up but I'm the only one working currently so she's got no chance off remortgaging on her own, where as I could afford everything on my own somewhat comfortably, plus I worked my arse off all last year in that garden to just sell up the following summer.

My mortgage repayments are £840 a month for the next 4 years and I earn around 35k a year so realistically with my house now being in negative equity (I'm not going to get it looking better than it was by the time she wants out), what are my chances of getting accepted when remortgaging in my own?