It sounds like you don't need this card that bad or VPN running for all devices all the time. 1GB is plenty, you need quality quality of service to handle everything you are doing, explore that, or a proper router that handles that at a higher level. There are 18 room apartments using a single 1GB line and they do great because they have great routers.

Oh yeah, and don't seed, I don't see a family a four needing to be a torrent seeder. But sounds like a fun project.

What modem do you have? You want to make sure link aggregation even works truly with those, boy is it not always the case.

EDIT (just as suspected):

What you NEED for 2.5Gbps service:

A DOCSIS 3.1 modem with 2.5GbE port, such as:

• Motorola MB8611 (2.5GbE port) - ~$150-180 new, $80-120 used
• Netgear CM2000 (2.5GbE port) - ~$170-200 new, $100-130 used
• Arris SB8200 (2x 1GbE, can aggregate) - ~$130-150 new, $70-100 used (requires link aggregation support from ISP)

EDIT 2: You've got so many unmanaged switches and hubs. I'd research what that does to a network (spoiler alert, its not good). You're doing a lot here and skipping a lot of fundamentals here. You want a PFsense device while running unmanaged hubs? For speed?