Eligible for a free equipment update

Comcast has been sending me "You are eligible for a free equipment update" messages.

For several years I have been running with modem Arris TG1682G (in bridge mode with my own router), DVR Motorola RNG200N, and the 300 Mbps plan with HD service.

I like the current 'old' TV guide and I use the DVR a LOT with an add on 500GB (I think) external hard drive designed to be compatible with Comcast.

I'm nervous about making this move to a new equipment update and losing the TV guide I am used to and the DVR that allows me a lot of storage that I can keep as long as I want to.

What will I lose if I accept this new equipment upgrade offer from Comcast?

What will I gain besides the added speed they mention?

Will I be required to also change plans, i.e., go from the channels I currently have vs. having to choose a  new plan that may not have the same mix of channels?

Will the DVR provided have limitations compared to what I am used to. i.e., be in the cloud with limited capacity and time limits on the content?

Will a Roku work with the new equipment?

Thanks for any insight, advice, recommendations you can give me.