RandomBaritone

I'm flying Lufthansa Cityline OTP>FRA in a few days on an Embraer ERJ-190. Never been on one of these before, and I'm wondering whether the overhead bins are standard sized and will fit a 9x14x20 rollaboard? I'm connecting to a 747-800 and would love to avoid checking a bag if possible. I'll be in J on both flights if it matters. I'm aware the Embraer doesn't have a dedicated business section, but instead blocks adjacent seats as needed.

I'm also curious about the stated 8kg limit European carriers seem to impose on carry-on bags, even rollaboards. Is it ever enforced? It seems petty to hew to the international standard for size, only to impose a weight limit half what American carriers allow. I mean, the bag is going on the plane regardless. If it fits, why should the weight matter if it isn't filled with gold bars?

Thanks, and apologies if this has been covered elsewhere.