German here answering.
In Germany you have Freunde (good friends), Bekannte (acquaintances, literally "knowns") and Kollegen ("colleagues"). While Germans are usually happy to meet with their friends, it is a bit weird to meet with acquaintaintances or colleagues without a reason. It might even be the case, that one suspects you want something (usually money or another favour) from them.
So I'd suggest you organise a bigger meeting (might as well be virtual for now, during the pandemic) as an informal social get-together event. Just something along the lines of "Hey, me and some other people are meeting together to get a beer/coffee/whatever and we would be happy if you joined us". In that way, things are not "weird" and you can easily connect with people. At the end of the meeting, you can make arrangements to meet again.
Once people, especially Germans, drop their shell, they are usually super friendly and happy to meet. On the other hand, people that are not interested can just decline the invitation and I'd suggest not to pursue this further. Potentially they have their minds elsewhere and making new friends is not a priority for them now. Trying to force it would be incredibly disrespectful.
An additional bonus with this: You can potentially make friends with multiple people at the same time.