They lose the trail as soon as you swap. They won't even necessarily know you swapped to Monero in the first place depending which of those you use. But even if they do that's where their knowledge ends.
If convenience is your priority, you would be using KYC exchanges to get Bitcoin anyway. Not that I recommend doing that.
Highly depends on where you live. US wise, SAR reports can get thru finCEN to the IRS and trigger audits. They don't treat it as a like kind exchange either and would absolutely want a gain/loss report upon disposal into XMR.
If they know you swapped to it no doubt. Maybe you got hacked before the swap. Or lost your Monero keys.
Like I said I'm not recommending buying either Bitcoin or Monero with KYC in the first place. But your original topic was about difficulty in acquiring it and if they can follow you.
It's similarly as difficult to acquire non-KYC Bitcoin or any other crypto.
"I Lost my hardware key in the boating accident and didn't keep nemonic backup"
