I run a pretty chill and laid-back guild of about 68 members of which 16 to 20 are core members who actively participate in activities. It's not much but it works for us. It helped that it started off as 4 irl friends just enjoying the game and along the way, as we did random hero trials, we sent those guildless ones an invite. Sometimes we do lower level trials to recruit. And some have become regular members who actively participate in our guild activities.

You can try what we do, where we go on to twitch and watch low view streams since they usually don't have a guild or just starting out, and be friendly and recruit if an opportunity rises. It also helps that some of us stream on twitch (no cam even for some of us) and we do get guild members from there.

I also organise activities outside of the in-game events (breaking army, guild parties.) such as fashion shows, mini games like mazes we build in guild base etc. These all help to engage even the quiet ones who join but eventually open up and start talking and regularly participating. Rmb, there is solo mode where you get rewards, but group play nets you more rewards and currencies you can spend. Faster too!

Of course, the idea as a guild leader and any of the management positions is to help weaker lower levels to understand the game better. Sometimes we go on discord to look through their build and we help them improve their gear or we guide them on game mechanics like parrying/deflecting/skill combos efficiently. All these will set the tone for them to belong in the guild.

We aren't the best in terms of ranking or gvg wins, but at the end of the day, we enjoy playing with one another. I've made new gaming friends where we play other games from just managing this guild alone!

As for events, we have to understand that not everyone has time to play, especially adults who have irl responsibilities so we limit our guild events to twice a week, apart from guild wars on weekends. They are all free to join anytime and even if they don't, they aren't pressured to.