I am following pediatrician recommendations and doing mixed weaning. Maybe you can also ask your doctor. For the chair, I personally purchased the stokke Tripp trapp one from the birth, I chose it because it’s wood, it transforms as your kid grows and it’s looking not ugly at all lol
I started with porridge when my baby was 5 months. High chairs are all similar tbh if ur looking for something cheap then the ikea one is good does the job most food places have them too. Ive seen tiktok videos people have the ikea ones and they spray the legs etc to make it look better