I was in a similar position as couldn't get a builder as wasn't extending.
I am in no way an expert on this but will tell you what I did.
Firstly, wasn't working at the time so was around.
Started with a plumber who moved the boiler, smart heating controls, some new rads, flushed and balanced heating system.
Got a window company to fit new windows and doors.
These two things were essential given how cold the house was so knew how much we had left to spend after this.
Got electrician to confirm re wire wasn't needed. I needed him to move a Fuseboard as this was on a stud wall we wanted to knock down.
Got a carpenter who would knock and build stud walls. We weren't doing anything structural (too complicated and would require builder/engineer/money). Electrician came back to move plug sockets/light switches while this was going on. He was local and fitted me in around his other jobs. Charged by the socket/switch.
Carpenter knew a plasterer and organised him when he was needed but I paid plasterer directly.
Carpenter fitted kitchen and told me when to get electrician / plumber / plasterer to come back.
Carpenter did floors / skirting / new doors / understair storage.
One of them recommended a tiler.
Got it all painted at then end.
It all worked out. Was a bit haphazard and I probably overspent on the electrics. I was lucky that the carpenter was so good and really decent.