This is just the reality of web development. You'd have the same issues if you were developing a PWA. Blaming Tauri for this doesn't seem fair. It sounds like Electron is a better fit for what you're trying to do.
Personally I think the ideal scenario would be allowing developers a choice between: 1. Use the native OS renderer 2. Bundle a specific version of some renderer (most likely Chrome) 3. Use a shared library for the renderer (this gets a little trickier with sandbox-based security models, but allows Tauri to ship a renderer without ballooning the bundle size of each individual app)
As a user, I'd be happy with a combo of #1 and #2. Use the native OS renderer by default, but allow me to install a "known good" renderer if I run into problems. Since it sounds like MacOS and Windows both ship better native web renderers than Linux this would likely be an option mostly used by Linux users, who are on average more willing to poke around in the settings to enable a compatibility option.
That makes them also use less memory etc.
On the other hand, if you can work around browser incompatibilities then Tauri will give you a much less wasteful app.
Choose the right tool for your use case.