Awww do not feel guilty and do not give him up. You truly love him. I have been in a very similar situation, and here are a few things I have found
-Hardwood floor: Look on craigslist (always be safe and meet in public.) for maybe people giving away old rugs. Make sure the fibers in it are tight together, and not loose or splayed, as you said your bun chews. The best carpet I found as my buns do similar is the carpet they use in banks or businesses. The fibers are tightly bound and its pretty hard for the buns to chew. Its not the prettiest but it works. Just make sure you clean it very well if it is used, and don’t use chemicals on it. You can also check with some construction companies as they often times have to tear out pretty new carpet because a business no longer likes it.
– Vets: Look for a rabbit group of rabbit society in your area. Many of them sell Critical care, and its usually cheap. You will also need a syringe (one without a needle lol). This truly has been a life saver for my buns when I had no physical way to get them to a vet. I can not guarantee it would save your rabbits life if he is very sick, but if you catch your bun in the early stages of stomach problems, it can definitely help. There is also a feeding guide on the Oxbow website for it, or you can ask the rabbit society how much to feed your bun, as its based on weight. They usually suggest 1 part of the medicine to 2 parts water, but I usually do 1 part to 3 parts to help with feeding (it is much softer so easier to use with the syringe and bun seems to eat it better) and to help if there is also dehydration
— Other things you may need to prevent trips to the vet: Nail clippers. They sell clippers just for small critters. It may be a struggle, but it definitely beats rushing to the vet with a bloody bunny who broke a nail, as Ive painfully learned. Cornstarch. It helps with minor bleeding, including if you clip a nail too short. Warm water bottle (make it when you need it). Just put warm water in a bottle and put a cloth over it if you can. Great for a bun who is sick and needs help staying warm. Cold water bottle (make it when you need it) for hot days to keep the bun from overheating.
— I will say as a side note, if you can get maybe a credit card for serious emergencies, you may want to. Most vets offer Care Credit, but you need practically a perfect credit score to get it.
– Neutering: What I did was I applied for a credit card that was 12 month interest free. When I got it, I got my bun neutered and paid the card off over 6 months, then canceled the card when I no longer needed it. You do not have to neuter if you cant, but you do risk some aggression. My male rabbit only sprayed when he was around another rabbit, so you may be safe, but no promises on that.
– Carpet/supervision : Ive had all this with my buns lol. All love to chew no matter what I do. For fencing, I use “Tenax Mesh home and garden fence” but there are other brands. You can get it pretty cheap at construction type stores like Ace or Home Depot. Its plastic fencing so you don’t really have to risk your bunny getting cut or hurt on it. Only issue I have on it is buns can chew it apart, but it takes quite a bit for them to get through it. Ive replaced the line of it maybe twice in the last year and a half, and the roll lasted me for both replacements. I also had to make little pilards to keep it standing upright as it does bow out a bit, but I just got wood recycled from a construction company for that. They also sell metal fencing that is solid (not braided together with sharp points), but may be a little more expensive. You could try to make a fence out of tall cardboard boxes, as its easy to get those free from people who recently moved.
— Again going to suggest tightly bound carpet. We have put the carpet over our original carpet to protect it, and the buns don’t chew on it. Weve also tried moving blankets (we got free off of craigslist), as they are pretty thick. It worked well as the buns did not enjoy the taste of it, but they still dug at the corners of it.
— For escaping, if you can make the corner big enough for you to sit in there with him and him still have plenty of room to run, I would suggest doing that. He may be less likely to escape with you right there, and it would certainly be easier for you to grab him if he tries. I used to sit in my buns little fenced area and just work on homework on the ground.
I know the situation is difficult. I beg that you please do not give up on yourself or your little bun. You love him, you feed him, you care for him, and you give him exercise. You give him the essentials to live a happy life, plus the benefit of your love The bun may be part of your life, but to him, you are his whole life. You never know where he may end up if you try to find him a “Better” home, but he will always be happy with you, seeing how much you care for him!