Separate right of return?

I bought a notebook in B-goods from Notebooksbilliger.de in June 2019. At the beginning everything was apparently okay, but after a while problems with the keyboard became apparent (keys did not respond, touchpat did not respond). The problem occurred relatively irregularly, which is why I hoped that driver updates or OS updates would fix the problem. Since the cancellation period had already passed, I had asked the dealer whether the goods could be exchanged for an equivalent laptop for reasons of goodwill. That was denied.

After about 3 months the problems with the keyboard got too bad for me, it was not even possible to log on to Windows because some of the keys no longer responded, so that it was no longer possible to enter a PIN or password. So I sent it back to the dealer with a return label. He then sends it according to his own information for contract repairs.

Normally I'm more patient and can understand when an order simply takes more time due to more work. But now it's just too long for me. I had asked for a status in the meantime and in retrospect I would say that I was often simply falsified with false information. So statements came that the notebook had just been shipped from the Repertaur and would be sent back to me shortly. I received the notification twice (only on my own request), last year and this year, that due to a system error, the returns could not be sent and processing was delayed.

But I have to honestly say that I now have enough of it. On 04.01.2019 I gave the dealer a period of 7 days to send the device back to me. At first I made it so suspicious.

My question is, do I even have a special right to withdraw from the purchase? It's just too stupid for me, because I also have a strong feeling that the retailer is trying to avoid something here. According to his own information, he reserves the right to exchange them. The device should have been repaired twice within the warranty period.

You have set a deadline and if the dealer exceeds it you can withdraw from the purchase

https://www.haufe.de/recht/weitere-rechtsgebiete/wirtschaftsrecht/setzung-einer-bestimmten-frist-zur-nacherfuellung-entbehrlich_210_308210.html

https://betriebs-berater.ruw.de/wirtschaftsrecht/urteile/Angemessenheit-einer-Fristsetzung-zur-Nacherfuellung-30907

Thanks, this is very helpful.

Happy, greetings to you