"We often go to the museum."
Translation:Często chodzimy do muzeum.
It is possible that in some context, probably as a part of longer sentence it could work. Using "idziemy" in the same sentence as "często" is unusual.
'jeździmy' works. But it's like "technically it works". In fact... it sounds rather strange.
If you go to the museum often, what's important is that you go around the exhibitions and look at the exhibits. The fact that you went there by car or by bus is totally irrelevant. It seems strange to mention it. In a way "chodzimy" here is more like "We often attend the museum". Or even 'visit'.
This is really the most annoying thing I've come across so far in Polish.
Sounds fine, just less neutral, as if you were asked "So what do you like to do in your free time". Added.
"chodzimy" can translate to "we walk" or "we go", if we go on foot.
"idziemy" can translate to "we are walking" or "we are going", if we are going on foot. Sometimes also when the vehicle we use is totally irrelevant.
"chodzimy" can also translated into "we are walking" (but NOT going) if it's without any destination. Therefore, not here, as we have a destination.
Yes, this is confusing and difficult, I won't pretend otherwise. Anyway, maybe this will help: https://www.clozemaster.com/blog/polish-verbs-of-motion/