My Bitcoin Core is fully synced and I tried opening this wallet but get stuck on "Opening Wallet. Not sure what do next.
It's likely that Bitcoin Core was "rescanning" your "new" wallet with all the recovered keys in it... it will be starting from basically block 0... and this can take several hours to complete.
Check the debug.log in your Bitcoin Core datadir... you should hopefully see a bunch of debug lines like this:
...
2021-05-19T05:59:34Z [default_wallet] Still rescanning. At block 538973. Progress=0.525272
2021-05-19T06:00:34Z [default_wallet] Still rescanning. At block 544471. Progress=0.538657
2021-05-19T06:01:34Z [default_wallet] Still rescanning. At block 550317. Progress=0.555550
2021-05-19T06:02:34Z [default_wallet] Still rescanning. At block 555563. Progress=0.571671
2021-05-19T06:03:34Z [default_wallet] Still rescanning. At block 561564. Progress=0.590429
...
It should also give you an idea how how quickly it is syncing... note that the progress value is from 0 to 1.0, where 1.0 == 100%... so in the lines above... the last line was at just over 59% complete
