Ofcourse I would use a hardware wallet, but if I store them all on 1 wallet and I lose the wallet, or the house gets on fire and it burns, then I have lost those coins forever? Or are there still ways to get to the coins somehow in that case?
No. as long as you have the seeds, you are still good because you can recover that afterwards. The hardware wallet might get burned but you still have ways to recover it through your written seeds. So, you just won't keep the hardware wallet alone but you have to protect also your written seeds in some ways.
Writing the seed phrase on multiple different pieces of paper seems a good idea. If one gets stolen the thief still cannot access my coins. However, the downside is that if I lose 1 of the 4 parts of my phrase seed, I no longer have the complete phrase and it basically means I have lost the whole phrase.
Maybe, to tackle that problem the best solution would be write the phrase on 2 pieces of paper....divide them up into 4 parts each so I have 8 pieces of paper...1A,1B,1C,1D,2A,2B,2C and 2D and then store them all in separate locations. Would that be the best solution?
What I did, I just wrote those seeds altogether and back them up with other written seeds. I place the other one on a safe place that only I knows. While the other one, it's always with me.