We will see how that might be possible. Not sure of the RTE could / would issue a new visa for the new passport then, or if local immigration could do anything with an eVisa.
Did not have to prove any monthly income. That is also not part of the official requirements in the law - sufficient proof of at least 500k THB in savings is enough.
How long are you planning on living in Thailand. Either way, for the first up to 5 years I would suggest getting a reputable long term travel / expat health insurance from a reputable insurance company active in your home country. That way, you understand the contract, legal framework, and your legal rights better. Will help to make an informed choice and to get your money in case you ever need to.
Please rethink that. Don’t come to Thailand if you don’t either have spare money to spend and just enjoy life or a clear plan and ideally (remote) job to make income. Many jobs / particular lesser qualified ones are reserved for Thai people. Sure, on some of the island destinations you mentioned quite some foreigners don’t seem to care about such legalities - but that would put you on their mercy and only put additional pressure on you. Also, Thailand isn’t the right place if you are already in a difficult phase close to depression. In fact, Thailand has a very high rate of people having mental issues as it is and very poor infrastructure to address such severe issues. Remember: You always carry problems and your state of mind with you - and a place like Thailand with its easy access to legal and illegal drugs can quickly only make things worse. I understand your love for Thailand. But I would suggest to take care of yourself, first. Then make a plan. And only then come and enjoy. Wishing you to get well.
I can't really give you an answer as to the legalities based on the information given. I can only try to cheer you up by telling you, that learning a life lesson for 70k THB maybe money well invested into the future - so I would not look at it lost, even though the money is gone now. Some eye opening relationships have cost people much, much more in Thailand. But I can only imagine that the pain of betrayal and lost love weighs even harder on you. Sorry you had to make such experience.