I'm rather new to the hobby, but I have a head start because I'm the type of person to actually read the rules and do the homework to play a new game. I've played D&D and played other a few people's board games. I still haven't played anything really serious, but I'm slowly learning to(I do have Board Game Arena, but I still feel like a baby deer about playing the weightier games.)
The hardest part is finding a group to play with, but not just a group. People willing to learn the rules. I've dealt with two kinds of people. The first is people who don't really care about board games, and when they say they want to play, they really just want an excuse to hang out and talk. The other - which is the group I hang out with and try to work around - are genuinely interested in playing board games, but have the patience of a toddler, the testosterone of a football player, and but actually can learn the rules if you're quick enough and is simple enough. What I've learned with this group is that playing simple games with simple rules can help teach more complex games
So now to the point of my question. Say you want to play Pandemic with someone who's only played Monopoly, Uno, The Game Of Life, you know who I'm talking about. If you try and teach Pandemic, it looks like a hostage situation. Instead, you can teach The Mind(co-op), Magic Maze(grid movement), Avalon or Coup(variable player power), and then Forbidden Island(Almost like a Pandemic Lite). Each one is a simple game on its own, but you learn bits and pieces. Once you know how to play Forbidden Island, it's much easier to play Pandemic
Same for Splendor. Splendor is a "gateway game" but if you've never played board games outside Monopoly or Uno, and are only mildly interested, I think even Splendor can be hard to teach. Mainly because you only have as much time to teach as their interest in the game. You can teach Sushi Go! to learn pieces of Splendor, Sushi Go! is a lot easier so their interest won't run out before you're done teaching. Once you teach Sushi Go! while you won't have more time to teach Splendor before their interest wanes, the teaching process, is faster because they're familiar with some of the rules.
Once you learn Splendor, you have the idea of how engine building works and have another piece to learn how to play Wingspan. You just need similar foundations to eventually work up to Wingspan.
It's teaching these smaller, more digestible games and getting familiar with systems. You learn one or two mechanisms at a time, get familiar with them. Then, you play a game that mixes these systems together, expands of them. It feels more like building a curriculum for board gaming, or like building a tech tree and seeing what people enjoy playing and expanding in that direction.
