10gb Question - Same subnet hosts through GW or no?

Think my logic is correct but want to clarify...

My GW default router is Fortigate 100e, handling all l3 routing... no 10gb capability.

My switch stack, 3750X-48 acting as L2 devices only minus a l3 int for management vlan that’s same as FG.

If I put a 10gb switch in the mix and trunk that to the 3750 stack, if two hosts are on the 10g switch, and are on the same subnet... since that is just l2 they won’t even hit the gateway to route traffic between the two and 10gb speeds would be achievable pending the obvious disk factors etc, right?

I don’t know why but part of me feels like I’m wrong , but it’s been a long week.

For instance 10.10.10.1 is 10gb connected to 10gb switch and so is 10.10.10.2 , but the GW is on a stick at 1gb, shouldn’t matter unless trying to go to a different vlan?

Cheers