As of now we don't have any evidence that neither supports or opposes Ash catching beyond 6 member team so I think it's best not to speculate like he will.
There are actually a few hints that he may be getting more than 6.
1.it's all but confirmed he's getting sobble which gives him a team of 6(If we're counting Mr mime since we haven't gotten a definitive response if he's a member of ashs team or not)
2. It hinted in the ending that ash might also get grookey( I know the ending is just a word game but the fact that they had grookey next to 2 of ashs Pokemon and went out of their way to make it dusk lycanroc proves to me that it might be a hint of things to come)
3. There has been an upsurge of tyranitar merch recently which has lead some to believe it will also join ashs team( this is the most flimsy as we can t be sure if tyranitar will play any important role, let alone a capture)
4. Ash directly states in a previous episode that he wants to catch a lot of Pokemon and there isn't any reason to throw that line in there if he was only getting 4 captures(since he started with pikachu and Mr mime)
5. As we saw in the riolu episode, ash doesn't have his Pokemon with him at all times as dragonite was left behind at the institute when ash went to look for eggs making it extremely easy for them to give ash more than 6.
6. Since sobble would give ash his team of 6, I seriously doubt there gonna go this whole series giving ash only one Pokemon from galar. Regardless of the all regions theme of this series, the galar Pokemon are the most marketable right now and will probably get the bigger spotlight
I agree. It's just simpler that way since it sets perimeters on what is plausible and what is unlikely. As for the recent talk about Satoshi getting a Dorameshiya, I just don't see it being necessary since it wouldn't offer anything new to the table. I'm a huge fan of that evolutionary line, but if Satoshi ends up getting one I don't think it would stand out from his other Pokemon given that it would likely be overshadowed by both Kairyu and Gangar.
While I agree that it's unlikely that ash would give a dragapult since it offers nothing new, I don't think that it would be overshadowed. Even though this series takes place in all regions, I think that any Pokemon ash get a from galar would probably get more spotlight since they'd more marketable right now being from the current gen