How to improve slow chain sync for full node?

I'm running geth 1.10.25-stable on a Mac with geth --authrpc.jwtsecret ~/Documents/jwt.hex --mainnet --datadir ~/Documents/geth --maxpeers 50 --cache 8192. I have had the most success with Lighthouse as a consensus client, so I am using Lighthouse v3.2.1 with this command: lighthouse b --network mainnet --datadir ~/Documents/geth --http --execution-endpoint https://127.0.0.1:8551 --execution-jwt ~/Documents/jwt.hex. I have forwarded ports 30303 and 9000 to the host machine.

My problem is that I have only 35gb of chain data so far after running this for 3 days.

Lighthouse shows 60-80 peers. When using geth.attach net, I always have 18-22 peers. My est_time for sync completion shows 4-5 days in lighthouse, but at this rate, I can't see this completing in under 10 days--probably longer. My ISP speed is gigabit, and I get close to that when checking. I thought a firewall might be the issue, so I think I ruled that out by port forwarding and verifying I have a decent number of peers for both consensus and execution clients.

As for hardware, this is running on a machine with an internal PCIe-based SSD, 64 GB of RAM and a 6 core intel xeon.

How can I improve my sync speed?