These two points kind of go hand in hand honestly. Growth is not going to happen so much by continuously doing in house events, and/or setting aside playing time with other community members on fun games. What that will do however, is keep people around as they will see fun activities happening on the regular that theyre welcome to participate in.
Back in the 2019 era of Steam-Gamers when we were churning out community/server events left and right (we were running like 2-3 a week lol), the events were very populated and we were constantly getting new and old faces showing up to them. Black Rain had started the frequency of events by revitalizing the Events Team back then by asking everyone to shoot for making 2-3 events a month, when we had a team of about 4-6 people.
Around the september portion of that year, some new EMs were appointed and we kinda went away from the mandated 2-3 events a month quota, which didn't hurt right away, as people were still pushing out events left and right, and it allowed people some time to set up some more high quality, or complicated events.
Somewhere down the line, less and less events kept getting made, and by this point idk what the state of the team was like as I was a year or two out of the internal discussions, but if I had to guess, I would say people holding that rank were again not being held to making/pushing out events. I mean hell, the entire Events forum got removed, and the team was shot and buried after being turned into Expansion Committee.
To finally get to my point of dredging up all this past shit, in order to bring players in the community together, and maintain new members, you need to have those 5+ people that are willing to run at least a single event per month, and you need the coordination to not plan them all on the same day/weekend. Events could be as simple as a monthly movie night, GTAV sumo, playing Town of Salem, Among Us, Jackbox, anything. Hell, you could even just make an event to hop on one of the servers for an hour.
Currently you might not get much turnout doing this, but you can also see what events people are currently interested in by running them and also ASKING BEFORE taking all the time to plan and show up to coordinate such a timeline. The one thing you do need though is for someone to show up at the time you plan to do something. I saw too many times towards the end of the events era of SG that times were being planned upon, and then nobody, not even the coordinator, showed up.
TLDR: Get people to make events (dont matter how), and make sure people show up for those events. Have a backup coordinator or designate 2 people able to run the shit in case someone can't make it. This will help to retain new members once you figure out how to get them to show up on discord/forums.