My son isn’t talking! Please help!

So my son is 22 months old and is barely saying words. He understands everything I say and knows what things are. He can say kitty, mama(rarely), dada(rarely), choo choo train, boom, hop, and he says vroom vroom for car. He has hit every mile stone early. He crawled at 6 months, walked at 10 months. But now he isn’t talking. I brought this up with his doctor at his 18 month appointment and she said she’d tell a speech doctor(Idk the technical name) and they would be in touch with me but I wouldn’t get an appointment for awhile since of covid.

Anyone else’s toddler going through this? Did they eventually start talking? He only interacts with me and my husband, and occasionally my mom and sister since of covid so I also feel like that has something to do with it.