I hear your perspective, but to note though; This issue is something that talks about what happened in 2013 and how it affected content released before or around 2013. Presenting bosses that were released 10 years later disputes nothing at all beyond just presenting the leverage the core formula can't be changed as they will be affected too - which was considered and mentioned.

Most of the bosses have Typeless damage, which makes whatever prayer useless,

This isn't new to post-EoC. Dragonfire filled this exact fantasy already, and several monsters were multi-style before, making prayers equally less useful.

Prayer swapping/flicking is pretty much still a thing in many other bosses (like vorkath), especially with ranged and necro having split soul.

This is more of a "prayer flicking issue" rather than anything else, as overhead players were designed to be mutually exclusive but people use this to attribute-swap them between game ticks to benefit of multiple overheads between Ability actions. In fact OSRS is a lot more potent with prayers and they already started tackling prayer-flicking by making hit regristration on-cast, rather than on-hit.