Costco Members: NETGEAR Nighthawk CM1100 DOCSIS 3.1 Cable Modem + Free Shipping + All other networking deals for 1G network $109.99

Costco has CM1100 For sale at 109.99. This has two ethernet ports at 1G speed. On xfinity you can only use one at at time.

https://www.costco.com/.product.1290299.html


But technically you cant use more than 1 port which is limited by ISP. But CM1100 supports link aggregation which means you can hook up two ports in a supported router and get 2*1Ghz port

Here are the rest of deals with analysis
CM1000: 1Ghz with single ethernet port (Best Price: 119 on newegg with SPECIALWH promo code. Amazon: 139)
CM1100: 1Ghz with two ethernet port: (Best Price: 109.99 costco, Amazon: 129.0)
CM1200: 1Ghz with four ethernet ports (Best price: 129.99 Newegg with SPECIALWH promo code. Amazon: 149)
CM2000: 2.6Ghz single ethernet port modem (Best price : 179.99 on newegg with SPEICALWH code. amazon: 199)

CAX30 - 1GHz modem with AX2700 wifi inbuilt router (Best price: 199 costco)
CAX80 - 2.5Ghz modem with AX5300 wifi inbuilt (best price 409: newegg, amazon 429)

RAX45: 4.3GBPS wifi router but only supports 1Ghz link between router and modem
Archer11000: TPlink ax11000: (Best Price: 249.99 on costco)

Arris S33: 2.5Ghz ethernet port modem. Expired deal of 149.99 on amazon and bestbuy. But will show up again for BF

Motorola SB8611: 2.5Ghz port. 170 on amazon, 159 on newegg with SPECIALWH code

YMMV: xfinity 900MBPS - $40/month. 600MBPS - $30/month, 1.2GBPS: $70/month

I am going with xfinity 900mbps + CM1100 + RAX45

These are the only combinations that work without any bottleneck. Rest all are future proofing only and doesnt give you any benefit
Best price: xfinity 900MBPS+CAX30 --> Best price but lot of complaints on disconnects with this model ($199.99+$40/month)
Best compromise: xfinity 900MBPS+CM1100+RAX45 --> ($249+$40/month). Future protection with link aggregation
Best BW: xfinity 1.2GBPS+CM2000 or arris S33 or MB8611+AX11000 --> ($400+$70/month)

Buying a 2.5GBPS modem without a router is of no use. So dont spend money on CM2000 or CAX80 or S33 or MB8611 if you dont have a router capable of handling it.