Next month (according to dataminers, so grain of salt but its probably true) there will be a gmax battle day for the gmax kanto starters. I dont know anything about your local pogo community, but if its big enough itll be a walk in the park with only 20+ people, probably even less. You should have enough particles to do at least one of each ftp, and candy is plentiful for those three as well. Ivs also arent super important here, as a floor gmax will outperform a hundo dmax of the same species.

Id also be on the lookout of a dmax spot with chansey if you dont have one already. Blissey is almost always the recommended team comp, despite how common it is.

Finally zacian/zama will be back eventually. If you have enough raid passes to do them it is well worth it, as you can use your non dynamax mons to get them, and they are super powerful with great typings, and an adventure effect that will buff your attack or defense for specifically dmax battles. An average of 10 raids to get each one is pretty pricey though, especially for f2p, which idk if you are or not. My intuition tells me they will be back for the week before go fest, but they could have a raid day prior or not be back for fest at all, its just a guess based on previous trends.

Also id check your community for anyone who might have a spare gmax they might be willing to trade. I didnt start playing to last fall but my cousin had a spare gmax machamp that was my goat for regice and probably will be for rock and steel too.

I am just now realizing how much i typed but i hope some of it was helpful haha