Be careful with any rope toys,many are cotton especially with dog products
Plus a lot of ladders have gaps which aren't safe!There are some really good DIY toys though,no matter how creative someone is or how skilled they are with DIY
Something I'd recommend trying is drilling holes into natural hamster safe wood pieces,adding safe seeds to the holes,and stringing them onto some jute/sisal/hemp.You could even do this with untreated grape vine if you wanted.
Foraging clusters using toilet roll or Carefresh crinkles and bits of safe treats or food are also a great idea,just squish together your preferred material and then for tiny seeds like millet or flax seed just sprinkle them through or for larger pieces you should be able to create a hole by hand in the mass of Carefresh crinkles or toilet roll.This isn't long lasting but is still fun to make and can be an affordable option,plus you could do this with the toilet roll already given as nesting material and add an extra bit of an enrichment!