Synology offers two options for expansion cards: SFP+ and 10GBASE-T (RJ45). Probably the easiest way is to get a simple 10G switch (either RJ45, SFP+, or a mixture) and hook your RJ45 10GBASE-T from Mac Studio to the switch and connect the Synology to the switch. Your router doesn't need to be 10G capable so long as you aren't crossing VLANs. If within the same VLAN, the switch will handle all the traffic. If you go the SFP+ route, a simple DAC (direct attach copper) cable is all you need.
My 10G setup is a Synology RS1221+ with an E10G21-F2 expansion card that has 2 SFP+ ports. I connect both of these in a LAG (link aggregation) to a Ubiquiti UniFi Aggregation Pro Switch. The AggPro has a UACC-CM-RJ45-MG adapter made by Ubiquiti that converts SFP+ to RJ45 and sends 10GBASE-T to my Mac Studio over about 40m of CAT6a. Another one provides 10GBASE-T to my wife's MacBook Pro over about 25m of CAT6a. She is using a SonnetTech Thunderbolt 10GBASE-T adapter.
The link aggregation lets us both pull 10G separately. It won't allow you to pull 20G -- just 2 streams of 10G to separate connections. I have 8 8TB Synology HAT5300 drives in RAID10 array and get about 900-1000 MB/sec write speeds and 1000-1150 MB/sec read speeds.
I will say that 10G is pretty awesome. It can get expensive though. First, you'll need a Synology NAS that supports an expansion card to be able to expand to 10G since most of their devices (except really high-end) don't have 10G built in. Second, you'll need a switch to handle 10G.
Probably the cheapest option is this:
https://www.amazon.com/MikroTik-CRS305-1G-4S-Gigabit-Ethernet-RouterOS/dp/B07LFKGP1L (I'm not getting any reimbursement by you ordering through that link). Getting an SFP+ to RJ45 adapter will allow you to hook up your Mac Studio. Your router can hook to the 1G RJ45 port. Again, as long as you aren't crossing VLANs doing interVLAN routing, then 10G can be handled by the switch and bypass the router.