Hi, I was in a similar position. I grew up in a small town in the countryside and big cities have always made me uncomfortable. It was important for me to find a uni that felt like home (campus based, surrounded by nature, felt 'smaller') I have a (fairly long) list of universities that I deemed 'rural' enough for me from what I found online. I'll spare TSR the whole list but I'd be happy to discuss them further if you DM me.
Most 'rural' unis on my list didn't make it to the "further research" stage but there's a few I have more detailed knowledge of:
-Bath spa (I ended up applying to Bath uni instead, wish I hadn't and only did it for my parents. Bath spa is literally in the middle of a field so I'd imagine the student community feels more close-knit because its quite secluded.)
-Exeter (The campus is very green, I've heard 5 trees per student or something. I don't know what its like in the city as I've only done a virtual campus tour)
-Bangor (I applied there and visited it. Some people call it a city and some call it a town, its definitely a town, feels small. Great views of Snowdonia from the campus but the town is grey and quite run down imo. Didn't like it after visiting)
-York (ended up firming it. I was initially apprehensive of the size but as far as cities go its a nice one and looks bigger on google maps than it actually is. After visiting I felt comfortable there. The campus feels like you're in a park, although most of the buildings are 60s prefab and ugly. I like the colligate system because you're part of a smaller community within the university)
-Durham (city is similar to York, a bit smaller I think but lots of old buildings and green space. The uni also has a colligate system)
-Kent (applied there. The campus is surrounded by greenery and they have a colligate system. I personally didn't get the right 'vibe' from it after open days but I have a friend who has firmed them and is very excited to go)
-Keele (did a bit of research, lovely location and great student satisfaction ratings. I changed my mind about the course I wanted and they didn't offer it there so didn't get beyond that)
-Surrey (close to where I live so I know Guildford well. Theres some nice green spaces in the town and countryside villages are a 10 min drive away. Town centre can get quite crowded but lots to do and a good train connections. Google maps probably could give you quite a good idea)
Overall, my tips would be to look for campus style universities (everything on a campus rather than city style where facilities are in different locations around the city/town) and consider unis with a colligate system, this means you will be part of a smaller community within the wider university community and can help it seem smaller, even if the uni has a large number of undergrad students. Also have a look at the arial view on google maps to see what surrounds the uni. Even if the uni is in a city, it might be on the outskirts or surrounded by large fields or forests which will separate it from the feel of a busy city. This can all make you feel more at home.