Hey there! Just reinstalled Windows, and now it seems like Bitcoin Core is letting in incoming connections. Currently, I see 38 inbound and 10 outbound connections. Is that normal? Is it safe?
This is safe, your node needs to establish outbound connections with other nodes to get the latest copy of the blockchain and stay in sync. You may have not allowed inbound connections before the reinstallation.
By default you can have a maximum of 10 outbound connections and 115 inbound connections.
Relatively safe as long as you're not using "UPnP" in router and Bitcoin Core settings to enable inbound connections.
If you somehow used that option, consider using "port forwarding" instead.
It's showing inbound connections, so yes.
If you allowed Bitcoin Core through Windows' firewall, then that should be enough setting OS-wise.
Usually it's the router or ISP that cannot map Bitcoin's P2P port without manual settings so your previous router settings must be intact (since you just reinstalled your OS).