I suppose a lot will depend on other factors. For example age and do you have enough pension contributions? 150K is certainly a good amount but if you are 40 and can only find work now and then, will it last until retirement and what then? Even owning a property outright still means you have to pay taxes, although Estepona seems to have reduced IBI payments.

you need to look into the requirements needed to reside in Spain such as health care and income etc
You will need to obtain an NIE number etc and have full private health care. A Spanish bank account with at least 3 months of income going directly into it and being enough to satisfy the authorities you will not be a burden on the state.
You will need to sign on the residents register within 90 days of living in Spain and meet all the requirements.
There are hundreds of people looking for jobs you have mentioned and if you're lucky enough to find bar work etc it will hardly pay enough. Have a long holiday in your chosen area and do the rounds calling in places to see if anything is available .

You won't need to show income if you have sufficient savings

Making a living is not easy from these 'occupations' and to be legal you would need to have a work contract or to be self-employed means paying contributions for pension, health etc.

More on property here
https://www.pellicerheredia.com/en/real-estate

I think you need to do a lot of research and not burn UK bridges. Good luck.

It can still be an issue: Within three months of your arrival in Spain, you have to go in person to a Foreigners’ Office (Oficina de Extranjero) or local police station to register and be added to the Central Register of Foreign Nationals. You will need to have a valid passport or ID document and be able to show documentation to prove that you can support yourself (and any dependants), and may also be asked to show evidence that you have private or public healthcare insurance.

As said, the biggest issue will be that money can run out quickly and if you don't have enough pension contributions might end up in pensioner poverty. That's why your age would be important to know.

Why not buy in UK and go travelling for a long holiday and see if it is for you?

Why not just rent in Spain?

I would look for a cheaper property, to have alot more left in the bank.

and not drink it all away when you realise that you can get a pint for € 1.50

We see so many of these sort of posts on ex pat forums, and it brings home how little UK voters, whether remainers or brexiters, know about so called 'free movement' and the processes and documentation required to move to, and live and work in a Club Med country.
I wish the OP the best of luck, and as has been said, do it all legally. At the end of the day it is not all that difficult, just different.
' lluego,
'o nonno.

I think you have done the right thing by enquiring on here and getting some sound advice/information. Your problem given your age is going to be that you need to work to get by. There is still high unemployment in Spain and casual work as you mention is highly sort after by Spaniards who of course have the benefit of speaking Spanish. There are some people who do manage to do just as you have outlined you want to do and they do get by and enjoy their life in Spain but there are also many that fall by the wayside, hence the less than positive replies I'm afraid. The area you mention I do not know I'm afraid so I can't help you with that. Many on here are self sufficient in Spain as they came here to retire with pensions including state pension which currently brings with it free healthcare. I wouldn't say give up on your dream rather make sure you know exactly what you are doing and get to know well the area you would like to settle research work prospects etc best way would be if you can having an extended holiday in the area using it more of a fact finding work exploring opportunity than an holiday. You never know it may lead to something positive if not then better to be forewarned, good luck.

in malaga they dont care about money in the bank, the reason that they gave me was that the money could be spent tomorrow. They were looking for a provable monthly income ( full contract or pension)