You could try over the counter lice shampoo for people. Every over-the-counter (OTC) treatment for head lice contains either pyrethrins (Rid or Triple X) or permethrin (Nix). They are an effective treatment.
Not knowing where you live and what's available. I do use the concentrate.
https://www.amazon.com/Martins-Permethrin-Livestock-Kennel-product_by/dp/B01M97TUYF/ref=sr_1_7?dchild=1&keywords=permethrin&qid=1631649509&sr=8-7...
I do use precautions and when it dries it's fine. I have used it on my birds, careful not to get in in their face. I'm glad you have read my posts. I would not post if it hadn't worked well for me. I had such a severe infestation in the past I'm sure if I hadn't started treatments when I did I...