Exec spawning does not make the 3a unbearable to use, it makes cold start app spawning time longer, mainly due to the eMMC memory and the SoC. It's very likely unrelated to your issue and does not affect app runtime performance.
As for your crash, you'll have to give more details of what's happening and what exactly is "a bit of browsing" so we can help. If the issue exists with Bromite too, then it's probably not Vanadium-related (upstream bugs do sadly exist). I suggest you clear storage of Vanadium first to see if that helps.