Looking for a job: Construction

The outlook is not very good I'm afraid. Unemployment is one of the highest in the EU here and the Costa Blanca is full of ex-pats in the building trade with requests such as yours featuring regularly on this forum. Hours are long and pay is low and many operate below the radar but you will not qualify for residency this way as you have to prove you are able to support yourself including having health cover. If you don't get residency before the end of 2020 it is possible that financial requirements will increase significantly.

Would I be safe going elsewhere then? What other jobs would there be and how would I go about looking?

Everywhere is the same in Spain. It is expensive to employ someone on the books and expensive to go self-employed as you would have to make monthly payments starting at €53 a month, rising to €275 after 2 years.

https://www.expatica.com/es/finance/taxes/freelance-taxes-471615/ 

I'm assuming that you are not fluent in Spanish so you would be restricted to ex-pat areas where all the construction ex-pats already live and compete with the local Spanish builders. There are adverts for various businesses on this site so it may be worth giving some of them a ring but the usual advice is to come with finances in place to support yourselves fully for the first year as you will be very lucky to get a job offer whilst in the UK.

Is there know way of even getting help with living costs if you go there just like the uk? I’ve worked in bars and all aswell but can they just pay you cash all year round and would it be enough to support yourself with rent and food and things?

There is no help available if you have not been contributing and if you do manage to find a cash job in a bar it is only likely to be seasonal and you will not be able to qualify as a resident so you will be an illegal immigrant. You may be able to get away with this up to the end of the year whilst your movements are not being tracked but once us Brits are checked in and out there will be a record so if you ever leave Spain after overstaying you could be fined and/or refused further entry. We will probably be limited to spending 90 days in 180 here without legal residency.