It’s going to be the standard answer, but hard to go wrong with a rapala knife. It’s all I used for years before buying a couple nicer ones. I particularly like the superflex version.
I have the small rapala, and really love the small thin blade for some things. It’s like a scalpel. The way it’s constructed, makes it harder to keep clean where the blade enters the handle.
Victorinox is really hard to beat. very utilitarian.
I also can’t recommend the regular (non diamond) victorinox 14” honing steel enough.
I clean ducks and take fish rib bones out with a 4" rapala. and a 6" rapala for geese. cheap to throw in the boat, truck and garage, works great. For most fish I use a litum ion knife so can't say how well they do for that but for Salmon I use a 9.5" buck fillet knife. Its not a Bubba but its pretty solid for half the price.
I use the 6" bonning Victorinox for big-game processing. i don't own one of the fillet knives but based on my experience with the bonning knives I would have to think that's a great option in this price range for a do it all 6" knife. I might need to grab one for myself now that I think about it.
It really depends on the abuse they will be put through and how long between sharpenings. Dexter is a good medium steel as is the KRKT, the work good on the boat, just need to have a sharpener handy after a few Halibut/cod. The bush fillets knives I have can handle quite a few fish before sharpening but the salt starts to get to the blade at the end of the trip. I keep a Kershaw in the kitchen for final cleanup. That thing gets wicked sharp - it sharpens easy but dulls easy as well. I don't have any experience around the Victornox or the Rapala knives so I can't say.
Opinel makes several sizes of their folding filet knife- simple, sharp, and a great option for the pack for boning out game in the field as well as working on items in the kitchen.
The No.12 Effilé Stainless Steel Slim Folding Knife is the perfect tool for fishing aficionados. The flexible blade, sharp edge, and slim handle make it ideal for filleting fish. The knife is lightweight yet robust, and its elegant design makes it a fisherman's favorite. Ready to set your catch...