We have a weeride (free off a kind chap on here, traded for some of the finest beers) for our little chap, nearly three.
It’s great! You do need a few mm of vertical headtube above the top tube, and I had to tweak the mount at the seat tube too. The seat is fine, the harness is fine though I rarely use it now he’s so big.
the other option seems to be the LOCT (little ones come too) but that’s more money.
wouldn’t ride much off road tbh, they’re sitting directly on the top tube after all so lots of bumps and chatter, but for the school run it’s great (until we get out Thorn three seat tandem next month 😀)
LOCT seems much more suited to of road so maybe look there