A very quick summary from my own trials: Fivetran is a rolls-royce. It works well, it is very comfortable, but is very expensive. Stitch, airbyte and Meltano (my tool of choice) all use open-source singer connectors, and so the main issue is often how well the open-source taps and targets work for you. A lot of minutiae suddenly surfaces.
I havenāt used airbyte for a while because I donāt want to run my own web server for the UI, but I do feel like it is UI-first. Meltano can be defined in code and I have been able to stuff it into Prefect. But you probably need some programming competence with those solutions.
There are a bunch of other options as well, without recommending anything in particular there is Rivery, Matillion data loader (not to be confused with the full matillion platform), Skyvia +++
That was kinda general, feel free to ask more.
Oh, and keep the API in front of mind when looking at the SaaS options.