How Many Weapons Per Turn

It‘s basically what the title asks. I have a player (fighter), who often uses three different weapons a turn. We play by the 2024 rules. In the rules glossary under Attack (Action) are rules for Equipping/Unequipping and I‘d like to know, what they mean RAW.

I understand, that with each attack, you can equip or unequip a weapon. Including the one free interaction, which can include equipping or unequipping a weapon (if I have that right), you could basically use three weapons. 
Example:

Longbow is equipped

-> Attack and use Unequip as part of the attack

-> Equip Scimitar as part of the Attack and Attack

-> Use free interaction to equip Scimitar

-> Equip Hand Crossbow as part of the Attack and Attack

Is that right? Please no wild interpretations or house rules, I want to get as close as possible to the way it was intended.

"-> Use free interaction to equip Scimitar"

I assume you meant "unequip" there since at this point your scimitar is already equipped. But yes, that's how it's meant to work.

Although in this case, you don't even need to unequip your scimitar since your longbow is a two-handed weapon, so even though you equipped a scimitar, you still have a free hand to equipe your hand crossbow as part of the next attact.

Unless the fighter had previously stowed the hand-crossbow pre-loaded, they’d need a hand free to be able to load, so stowing the scimitar is required. 

Quote from NoRailsJustTales >>

Is that right? Please no wild interpretations or house rules, I want to get as close as possible to the way it was intended.

 Do you want what's written, or what's intended? As written, it appears correct. As intended... the general intent that you can do the stuff you see characters in the genres that inspire D&D do, so how often do you see characters in other media doing that kind of thing (my experience is that you have the occasional character whose schtick is the giant collection of weapons, but most characters do not do a lot of weapon swapping).

Quote from Pantagruel666 >>

Quote from NoRailsJustTales >>

Is that right? Please no wild interpretations or house rules, I want to get as close as possible to the way it was intended.

 Do you want what's written, or what's intended? As written, it appears correct. As intended... the general intent that you can do the stuff you see characters in the genres that inspire D&D do, so how often do you see characters in other media doing that kind of thing (my experience is that you have the occasional character whose schtick is the giant collection of weapons, but most characters do not do a lot of weapon swapping).

 My uninformed guess as to the intention behind the rule is that it’s so that the Ranger isn’t prevented from wielding both their scimitars because they hadn’t stowed they longbow at the end of their previous turn. It also helps thrown weapon fighters. 

Quote from ThelenyiWhinlaw >>

 My uninformed guess as to the intention behind the rule is that it’s so that the Ranger isn’t prevented from wielding both their scimitars because they hadn’t stowed they longbow at the end of their previous turn. It also helps thrown weapon fighters. 

That seems plausible. In the end, the 5/5.5e rules allow you to do a lot of things that are probably not intended because it's hard to write perfect rules, and they decided it's better to make the rules permissive and trust DM and players to avoid stupid stuff than to make the rules restrictive and force people to come up with house rules for entirely reasonable things to allow.

Probably ok as long as he has the right levels, masteries, and feats.

Rule-wise that is correct and appears very much intended as well per SRD.

The new SRD 5.2.1 has a conversion guide from SRD 5.1 to SRD 5.2.1 for creators looking to update their materials SRD v5.2.1 - System Reference Document - D&D Beyond 

It contains the following text confirming that you're intended to be able to equip and unequip on each attack of the Attack action;