I have found JetBrain's Rider IDE[0] to be sufficient for development on Linux. It is not as heavy weight as Visual Studio but does bridge the gap of convenience that VS provides.
There's a couple extremely common plugins "everyone loves" that just murder VS performance and everyone blames VS and not the plugins.
I know people feel like they just can't possibly live without it, but the refactoring tools in VS nowadays are much better, so I encourage folks to test drive by going a couple weeks without installing ReSharper. If you still really miss it and are willing to pay the performance penalty to have it after that, go for it. But give VS a fair shake without it.
One of the reasons for this is you can't turn off the Roslyn-based MS engine in VS (which IMO is reasonable, since it's needed for a lot of stuff) so there are always 2 code analysis engines running.
That's one of the main selling points of Rider Imo, that it doesn't run 2 completion engines simultaneously, which makes it much faster.
Unfortunately Resharper is still far superior to VS with the quality and quantity of built-in refactorings.
Another thing with Resharper is that it seems to run synchronously, meaning if you type something and press the completion button, the suggestions always pop-up. A major pain point in previous VS versions is that this wasn't the case with the built-in engine.
Sometimes you just pressed the autocomplete button and nothing happened, because VS was still parsing your code.
Thankfully 2022 fixed this, and this is one of the reason I would never consider going back to the older versions.
Roslyn is extremely well tuned. (Anecdotally in any IDE including VS Code without ReSharper it's performance is incredible and hardly noticeable.) ReSharper's performance problems are ReSharper's performance problems.
Blaming ReSharper's performance on Roslyn is just as wrong as blaming ReSharper's performance on Visual Studio. It's pointing the finger at the wrong thing in the stack.
Of course that's a big selling point for Rider. It's incredibly wonderful marketing luck that almost all of ReSharper's performance problems get blamed on Visual Studio itself or on Roslyn and almost never directly on ReSharper. As long as people keep pointing the fingers away from the plugin, JetBrains gets just about free marketing from every VS performance complaint real or imagined. Their incentives aren't aligned to improve ReSharper performance when "everyone" just answers "Just switch to Rider already" because they mistakenly blame Visual Studio rather than the ReSharper's own engineering.
For further comparison, I've also used JetBrains products a lot over the past few months. They are also solid and work great.
On the one hand this is great for cross-platform development (as is the topic here), as VS Code is about as cross-platform as it gets.
On the other hand it feels increasingly interesting/weird/almost-sad that the expensive flagship of the VS brand sometimes seems to be left behind by its tinier, free (as in beer and speech) counterpart.
I don't think your theory is entirely correct, but I think some of it applies here: VS Code started as an Azure project (the core editing experience Monaco was designed for the Azure Portal first and foremost) and seems to get a lot of love precisely because of its cloud synergies and its place near Azure's heart. It does seem to have captured the hearts and minds of most of Microsoft's best tooling engineers. That said, it's possibly the most "Developers developers developers" they've ever been given how much of that tooling is now cross-platform, isn't tied so much to Windows specifically, and isn't tied as much to Microsoft-only languages either.
Really there’s three important factors in perceived VS perf issues:
1. Your codebases have gotten bigger. More projects in a solution and more code in a project means more work the IDE has to do. Various components have their breaking points and it’s not uncommon to hit them.
2. VS is really really really really big. Some components in there run like a well-oiled machine. Others, like those last touched in 2013 and with less than 10k users per month, are rickety and will freeze your UI or cause the GC to freak out or both. If you’re one of those 10k users, whoopsie!
3. For many years the mandate in the VS org at Microsoft was that of a feature factory. That changed around 2016 or so, maybe a little earlier. But cleaning up a decade of feature factory work while still needing to innovate on a growing userbase that throws more and more at the IDE each year is hard.