It's way too early to book anything over two years out. In the meantime, if you haven't done so, use your time planning your trip. Read guidebooks and search the internet to lay out your itinerary. Where do you want to go, what do you want to see? Get input from the family so everyone is happy.
I've spent the past year, fantasy traveling to make an itinerary, actually three itineraries for three alternative trips both for 2022 and 2023. I made a Itinerary word doc for each of my proposed trips which includes itinerary with dates, what to see on each day. Then I also make a To Do doc which includes a list of hotels, sightseeing, transportation costs all based on today and will be updated as things change. Finally I have a Packing List doc. I'm constantly tweaking the lists. You can tell I have way too much time on my hands because everything is color coded, LOL.
I'm not an experienced traveler like many on the forum, three trips to Europe in 50 years. But I feel I did a good job planning our Italy trip in 2019. When I am fantasy planning for 2022 and 2023, I find that most hotels were not booking beyond a year out. Airlines book about 11 months out, some less. Many sites are closed so there is no prepurchase of tickets. Even if you could book anything, you will want cancellable/refundable and not pay for anything at this time. After all the problems people had with refunds last year, I'm not willing to risk it. I already had a thief travel agent steal tour money five years ago. I don't want to go through the problems of trying to recoup money again. That said, I'm glad you are doing your own planning. The planning is part of the fun of traveling.
There's a concurrent thread with planning trips which may help https://community.ricksteves.com/travel-forum/general-europe/best-planning-tips-and-tricks