+1 for MTU and persistent keepalive. The last one helps if the connection is lost after a certain amount of time and does not recover, the first is often the problem when connection is intermittent or just “weird”.

Setting MTU requires knowing the MTU of your connection. Many ISPs provide IPv4 encapsulated in IPv6 protocol (Dual Stack Lite, I believe), meaning that from the regular package size you have to deduct the overhead of the encapsulation and if I remember correctly, also the package overhead for wireguard.