There's around 6 of us in my friend group that regularly like to play together. Until Dice comes up with something better, here are the least painful options I've found for us to play in the same match:
One of the easiest options is to go to the "communities" menu on the main page of the game. In that menu, there are always a couple playlists that you can join and these put you in persistent lobbies so everyone stays together from match to match. The only thing is those playlists change every few days. I believe right now the playlists are Hardcore Breakthrough and Infantry Conquest. You'll also need to first join with one squad and then get the second squad to join through you so they get in the same match (after that you'll all stay together from match to match). The odd thing about the lobbies from these community playlists are that even though they are persistent and don't disband, they don't appear in the server browser. That's an unfortunate decision by Dice, but it is what it is.
Another option is to go to the server browser and look for a lobby there to join since those also are persistent so you'll stay together. I will mention the server browser filters aren't very good and tend to reset often. However, the most important filters to select are your region and also set the "player slots" filter to "Any" otherwise you won't see any of the full servers. Also, go to the other tab and select the filter for your game mode such as conquest. After that then filter by player count and hit the refresh option. There seems to be mostly hardcore conquest and conquest lobbies in portal. Once your squad joins a portal match then the second squad can join through you to get in as well. They can also find the same lobby in the browser and join directly but often they'll end up on the opposite team when doing that. One other thing to mention is that there's no option to switch teams if you end up on the opposite team as a friend. So if you end up on the opposite team as a friend, the only way to switch to the team they are on is to leave the lobby and try to join again through them...you might have to also get into their EA squad and try to join through them. If there is an open slot on their team then it usually will put you in their team. If there's not an open slot then you'll sometimes end up on the opposite team and will have to try again.
Your other option regarding portal is to create your own portal server and have your friends join that so you'll all stay together as well. If you set it to have backfill bots, then you'll need at least 8 of you to get the match to even start. If you don't have it set to backfill bots, then you'll need at least 20 players for the match to start. So that isn't a very good solution unless you've got a ton of friends to join.
One other thing we've done is we'll have two EA squads of people waiting in their lobbies, then we'll have the first squad's leader select to join a match. The second squad's leader will be in bf6's social page and have the first squad leader highlighted. Right when the second squad leader sees the first squad leader's social page show what match they are queueing into, then that second squad leader will press the "more actions" button at the bottom (on console this is "left stick in")...and they should see an option to "join game". So if they press this quick, it'll pull the second squad into the match that the first squad is queueing into. There's two wrinkles currently with this. One is that at the end of the match, both squads will need to exit and do this process again to join the next match together. The other wrinkle I've found is that if you're on Xbox, the "join game" button doesn't seem to ever appear if you're trying to join another Xbox player. The button does seem to always appear if an Xbox player is trying to join a PS5 player and probably also a PC player. Alternatively if a PS5 player is trying to join on a Xbox player, the button sometimes appears but often does not. If a PS5 player tries to join another PS5 player, the "join game" button does always seem to appear. So long story short, there's a bug where an Xbox player won't get the "join game" button while trying to join another Xbox player and it also sometimes happens if a PS5 or PC player is trying to join an Xbox player. So the solution to all this is that the main party leader of the first squad would need to be someone on PS5 or PC (so the "join game" button always appears for the second squad's leader) to get this method to work until Dice fixes this issue. I've already reported this join game bug so hopefully it gets fixed at some point.
This is pretty long but those are the best ways I've found to play in a larger group. Hope this is helpful.
