It's not only a matter of doctrinal errors, it's also a matter of how we meet. I'm very much passed guided singing to God for 45mins, sit down, listen to a sermon, alter call, feigning communion and having small talk before ushering to our homes for the week. Yes, we have weekly small groups which is made to make up for what doesn't happen on a Sunday which then somewhat makes the Sunday service redundant because it is, and also has been what happens at the mid week small group truly communion of the saints.
I really hope this covid situation has caused the church to really rethink how we gather because at least for me, and a growing amount of people I know, it' can be shallow, dry experience.
People often can misinterpret what I'm saying as back sliding or as you mentioned 'forsaking the assembly' but it's quite the opposite. It's search for and desiring much deeper connections with people, real communion, not half a cracker and shot glass of juice...(that is not communion, it is a religious substitute) This usually can make people very uncomfortable because we are somewhat used to just scrapping the surface.
For those who are happy and content with the traditional (somewhat catholic) method of the saints gathering, I have no problem. I'm happy that they are happy and find it fulfiling.
But after many years, I'm not longer interested in feeling like I'm in a club.