From my experience:
Chopping - doable on 7s malus, but you have to make no mistakes, get a decent map and not spam but have a good timing on hits, not the easiest one.
Sickling - doable on 7s malus, maybe even a bit more, but depends on map rng, you have to get a bit lucky with "single" bushes close to each other rather than double ones. I also hate that they are sort of hard to distinguish quickly, they could maybe color them a bit differently so you can choose your path easier.
Stones - see chopping, pretty much same situation and outcome.
Fighting - you can get horrible spawns and not be able to do this on 7s with perfect hits, or you can get god tier rng and have them all spawn at the same side and complete it at 15s. Not a fan of this one, but most of the times doable on 7s.
Picking - the only one that I think needs some tweaking because a) why is this one using left click? and b) the animations are ridiculously long and limiting. I think I managed to do it on 5s or 7s with everything absolutely perfect, but most of the time I don't even bother if I'm there with any malus.
Watering/Hoeing - these are the money makers, both can be completed at 15s, but I wouldn't be surprised if someone managed to do hoeing on 20s malus, I definitely would try if I weren't too lazy. Watering one can be glitchy, especially on high server load where packet loss ends up eating your "hits", but if you do everything absolutely perfectly, it can be completed with a 14s/15s malus. Hoeing is fun because it has the lowest recovery time so you can spam click-move-click-move-click in 360 degrees, my current best is 109/60 with no malus I believe, but you have to get a bit lucky with map (or reroll it but I don't usually do that), you can get fewer than 60 open spots and then need to double hit some to compensate.
Either way, for anyone that has recently started doing these, don't worry, everyone absolutely sucked and then improved with practice.