Today (Good Friday, Central European Time) was the day, I attended church as a new believer for the first time in my life. I prayed since 2017 for this and after having been put through some really bad suffering for not making the step, it finally happened.
God set this up in a way that Christians of two denominations joined for service in the baptist church he pointed me towards in 2017 already, so I could essentially hide in a crowd filling up the entire building, without anybody noticing me not belonging there, avoiding triggering my diabolical social anxiety. It was still a hard fight, even after being in front of the church, I again walked away multiple streets until the road turned and I ended up in front of a hedge. I spoke Lord's Prayer and He made me turn around and go back in.
The Christian guests also brought their pastor doing the sermon and it was a tremendous uplifting experience. I was fully participating in the service, as if I already knew what I was doing, including singing, praying and listening to the sermon, where God spoke through the pastor to me, why He had to put me through suffering.
Now I know the parish leader/chairman of the church, who was present as well. I had to introduce myself alone, because I know absolutely nobody in my social circle with any connection to any (Christian) church. When the regular pastor (whom's sermons I already listened to online) with the rest the community return from the church's Easter camp, the chairman is going to introduce me to them. So I don't have to do the "Hello, here I am out of blue sky!" thing.
Thank God for making this possible. The events leading up to this did really hurt badly, but were absolutely necessarily. Thank you guys for pointing me to the Lord and Savior here and elsewhere on the Internet.