Repeating the mantra that "grenspam is dead" is not a legitimate argument against buffing grenadiers to make them a more worthwhile investment.
Then how about this:
You want grens to stand up to rifles and tommies.
They are NOT supposed to, because if they did, we'd have grenspam meta all over again, not to mention the broken balance relations vs every single allied infantry unit.
Most of the buff gren suggestions would make them easily outperform all of allied core infantry, its pretty clear that will never happen for the faction with early access to best supporting units.
Grens will never be buffed, because that is against their design, they perform well for the cost and within the role they have, they win vs what they are supposed to win, they lose vs units they are supposed to lose, you want to win vs units they are losing? Add HMG or sniper to the mix and there, you're now winning, because this is how the faction is intended to be played.
If you're focusing exclusively on grens, which about every single axis fanboy goal here is, you'll have a bad time, because again, the faction is NOT supposed to be played like that.
Combined arms are used by the vast majority of Ostheer players, yet due to the recent patch we are seeing MG42s get wiped within literally seconds against the USF mortar.
Because USF mortar is fine and balanced

That is NOT an argument, that is an excuse, poor one as well.
The combined arms capacity of Ostheer is not that remarkable compared to its counterparts. The one build order fits all playstyle of USF right now is what hurts Ostheer the most, and it is quite evident in matches with the ubiquitous mortar+rifleman into stuart combination that creams any combined arms combination that Ostheer puts together in the early portion of a match.
Which again boils down to mortar, which is a balance issue.
Tone that down and you won't have issue. Period.
If a singular unit is overperforming, you nerf that singular unit, you don't buff all units it counters, because then you'd end up in buff loop for everything.
You can't see that, I can-thats why I work with game design and you don't.