alphamarine 3000 with hydraulic ram upgrade to what?

[hscrugby]

ok, i'm starting to admit defeat cause well, it's an old system and I don't think trying to throw money at it is worth it.
I can't tell if it's the "computer" part, the compass, or rudder sensor that's wonky. I found some old support/forum posts from google on what to test for and using those all of them "test" ok according to a voltmeter.
Even when it "works" it's odd at best. Like the dial is never the same but once she starts going straight on a heading like 30 degrees, I had to dial 90 one time, then 200 degrees the next. After a while it'll sometimes either drift slowly off course, or suddenly just go in a little circle. While motoring in open water not terrible, but if sailing, a surprise circle does bad things to sails/booms/etc.
The frugal in me wants to reuse/save as much as possible.
But I don't want to get an auto pilot that's rubbish by spending 1200$ when i could spend 2000 or so and get one that works way better.
I do have Garmin electronics currently, (but no working wind gauge at the moment) so thinking of leaning that way.
I guess it would be something like this?
https://www.thegpsstore.com/Garmin-G...ack-P4485.aspx
Then probably need to add a new rudder sensor? and it should tie into current drive?
I'm pretty sure she's too heavy to use this style, https://www.thegpsstore.com/Raymarin...lot-P4115.aspx
(Hans Christian 33t, which from online weighs anywhere from 19k to 26k. I need to ask next time I'm hauled out for curiosity)

Are there any "don't get garmin autopilots" type things? easy and lazy is the goal here. I mean, that's the whole point of an autopilot right?
I'm not trying to race etc, just want to say "go that way" and have it well, go that way.