The "aggro" drugs already have a reduced effect on a "good path". In my playthrough the only thing they've done is make the screen have a red tint for like a single render and then the everything is back to normal. Where if you are "bad" it's already having you show increased aggression.
I still don't see a reason why the collars need to be treated any differently than the forced punishments you have to do. Did the MC purchase that specific training book of his own volition or was it provided for him? The shadowy people were not expecting someone to not be a rapey asshole about the collars, they figured that whoever took the job would be keen on instantly controlling the girls getting them on all slaves route etc.
There is also another group that have just recently come into play that are likely opposed to whatever group is making the collars (they are sneaking around the school and clearly doing things that the school/shadow group didnt apporve of, which is another sign that you will be able to opposed the idea of collars.
A fair bit of the romance options would disappear. Hikari wouldn't want to be her boyfriend (you emotionally manipulate her and then collar her for basically no reason), Akemi would (rightfully) hate you for lying and manipulating her sister, Olivia would still be Olivia, Sasha would have trouble trusting you with ghost hunting. Cassie would stop talking to you when you turned her friend to a a borderline slave because she almost raped. Hell if any of the girls talk to each other they'll all know you are the same level as the creepy teacher (arguably much worse)
I've given you multiple ways that the story could go in both overarching "story direction/drama"(MC vs Shadow group, MC x new group vs shadow group, MC vs new group vs shadow group) and interpersonal drama (MC having to collar but then CHOOSE not to use it/how the girls react to that etc) as well as example as to why it would silly both financially and from a story (both in lore and overall game design reasons) all while showing that content that hasn't even made it into the game yet will still follow the option of "the player will choose". Not to mention none of the girls out of school stuff (Sasha ghost hunting/Olivia Bodyguarding so far) would take place because they wouldn't want to be around you unless they were absolutely forced too
If you can't see how the dev could work both "good" and "bad" into the game you either are
1. Someone who hasnt played the game and seen that there is very different content on each side both in entire scenes and especially in dialog (which fits with you only having played the route you did but still saying "x is always the case")
2. You don't want there to be "good" stuff and this is all in bad faith
3. You want to troll
I put those in order of likelihood but regardless there is no point in us further conversing you've made your point that you don't see how it could deviate from what you have in your head but have refused to engage in any way with any of the ideas I offered.