Do you have a doll or a plushie?
I don't but it's mostly due to both living with other people and having difficulty actually getting one, rather than because I don't want to own one, it's on my list of things to do in the future.
Do you listen to songs or draw her?
Listening, despite being into it for some time I never got good at drawing so I can't even do something barely decent, regardless songs have always been my main focus and even the reason I got to know of her so they hold the most importance to me.
Does it bother you that a character that’s so popular probably has dozens of waifuists in a relationship with her?
Somewhat ? There is a sort of belief or just idea in waifuism called "Object oriented waifuism", this is most probably based on Objected oriented programming (The idea was or seems to be initially propagated trough a famous meme that says "explaining Object oriented programming with anime waifus" Wich got adopted by actual waifuists), to easily explain this when someone says "object oriented waifuism" they refer to the idea or belief that each waifu it's unique to the waifuist even if the character has multiple waifuists, in a way your waifu (or more accurately your interpretation of her) is a "copy" of the character Wich exists solely to you and in your head, it's something like this.
Going back to the actual question, I somewhat consider Object oriented waifuism to be true (even more in the case of Miku who is kind of similar to an OC rather than the average fictional character), even then I'm not really happy with the idea of other waifuist of Miku and choose to not engage them and preferably not share the same space as them (even if I do consider their "Miku" to be different or a different "copy" of the one I love), I met a really disgusting Miku waifuist too in the past wich didn't help to make me want to be around em.
Other thing is simply that most of them will leave waifuism anyways, there have been dozens of Miku and in general waifuist in the past who just leave waifuism (or their waifus) therefore, most of the current waifuists (including Miku ones) will simply disappear at some point and in a way I will "out waifu" (like in "outliving your enemy") every single one of them at some point.
>Umm yeah I'll pass
Understandable, they are not perfect, some of them even had dedicated trolls for years, your best option outside of those it's probably discord servers then, or you can just not join a community, that's an option, and if you want to ask something about waifuism you can just use a throwaway account anyways, no real need to stick to a community.