how on earth do I keep spiders out of a rented house??

I'm not sure what sub to ask this in but it seems to fit here. I moved to the UK from Canada last year and currently rent a house that seems to be on the older side. I have very bad arachnophobia and and anxiety disorder the spiders here are bigger than in Canada which is making it much worse- anyways I see about 1-3 different spiders inside the house every. single. day. it's making me extremely paranoid to go anywhere in the house.

some are cellar spiders, some have the body shape of a black widow but aren't, and the worse ones are huge house spiders that are extreme fast.

I almost had it when I stood directly outside my kitchen looking at all the corners of the room before attempting to step in only to almost walk into a spider that was descending right in front of me from my ceiling!

I have no idea how they're getting in and no idea how to keep them out. please help!

I always tend to see one right behind the toilet in the bathroom [which wasn't sealed to the ground and would wobble. had to get the landlord to fix it] which made me realize that barely anything is sealed in the house, the floors along the baseboards, the counter connecting to the wall, etc.

I never open windows because there's no screens to keep anything out and never leave doors open either yet spiders ALWAYS find a way inside. the house started to crack since I've been here and the cracks are slowly getting bigger. are they somehow getting in through that?? it's both on the outside and inside of the house house.

conkers don't seem to be working and I've been spraying around doorways and windows with a spider spray to try and keep them away. sometimes I'll go a few days without seeing one and then the biggest one ever will just randomly spawn in. I'm so fed up with this I cannot live like this. it's causing me so much stress I'm so scared to walk around my house.