Hello Robin.
First, I'm sorry you struggle to find good language partners. Unfortunately, many people on this website are not really interested in truly learning a language. Many think it's dating site, others may use the platform for some days and realize learning and practicing a language requires someone to be serious, others are here just to troll and annoy people... My advice would be to read carefully the profile of the potential language partners before contacting them. Make things clear from the beginning. Is the person's need match with yours ? Example: if the person only wants to practice his/her oral skills and you want to practice your writing skills, both of you will probably end up frustrated. I think you also have to be realistic. can you really help this person ? Will you have enough time to do it ? Is what s/he asking is too much for you to handle ?
Second thing to consider is the commitment of the potential language partner. Does this person really want to learn the language ? Why does s/he want to learn it ? What are his/her motivations ?
To conclude, I would say that there is another thing to take into account : the personality. Language exchanges happen between two human beings, and sometimes personalities just don't match. If you are a very talkative person but your partner barely talk, or at the opposite if you are very quite and your partner does like to talk a lot, then again you'll probably end up frustrated.
So yeah, I suggest you to keep trying and to read carefully people's profiles.
Cheers !