Sure, marriage can bring lots of purpose and meaning to your life. It may even 'fix' you, for a time. However, it can also bring devastation. Being betrayed by who I felt was my partner in life nearly destroyed me, and years later I'm still struggling to find my footing.
Relying on union with another person is not, in my eyes, a viable solution for the long term. At best, you're punting the internal work that's truly called for down the road to another day.
No you don't. This is not a prerequisite for happiness or meaning. It's a narrow view on life to believe that the only way to achieve fulfilment is through marriage. Especially not even considering all the pitfalls involved, and all the risks of it making your life much worse.
Maybe it'll work for OP, maybe it won't. It's way too big of a blanket statement to just say "marriage will fix your problems".
That is it. There is no other solutions for you. Meetups, hobbies, social contacts, "experiences", ... They won't work. You will come back to an empty home at the end of it and discover the same old problems you were trying to deal with.
Just get married.