Why is the Development Experience in Power BI so Buggy compared to other BI providers?

It's a shocking piece of software. I have queries running that take forever to load. Have 25 queries - average 10 steps and most rows is 22,655. My machine is a beast, but it is struggling. Internet connection very fast. I have looked at refining queries which I have run the equivalent of in SQL Server on the read-only Dataverse tables and takes seconds. I personally think its a resources issue at Microsoft. Needs sorted as nearly unusable. I've also overwritten semantic model with updated query and it's fine until you run a data refresh and reverts back to old query. I have cleared cache etc. No difference. Now things are getting slower and slower as I try to fix the query - even putting filters on the source. Shocking - please for the love of God - Sort it out!