Since both ROKU and Firestick are about $40, I would buy both and test drive them to see what you like.
ROKU is a cheap entry into modern television services that has an easy interface and good customer support. ROKU has a lot of free content and since you have Netflix already you can connect that account and watch it on your TV - if you pay for Netflix streaming and not just DvD. Then you can just browse the apps offered and add channels you like. There are many free channels.
As for recording, all the programmed shows are always available so no need to record those, however live events are not always on-demand later on. You can pause live events for up to 90 minutes with a USB plugged in. ROKU is a good service, I however prefer Amazon.
ROKU:
https://www.roku.com/ If you have Amazon Prime already I would get a Firestick. They have an easy interface as well. As Badwolf said you can use voice to call up shows etc. and most of the content is free on Amazon Video, also there are many purchasable movies etc. Firestick also has free content/channels etc. that you can watch without an Amazon Prime account.
Amazon has a device called "Recast" that would be your DVR for live or local channels. Its usually about $299 and is a high quality DVR that can record 2 shows at once etc. similar to what you describe you use now.
As for racing channels I just don't know enough to say what is the best service for that. I know with Amazon you can use the MotoGP app, but you need to purchase a "video pass" to access a lot of the content. The amount of content available there however is impressive to me, but again I don't follow the market. Look at their website and see what they offer, I linked it below.
MotoGP website
https://www.motogp.com/?_ga=2.265105359.1504286342.1616956930-1556900044.1616...Recast:
https://www.amazon.com/Fire-TV-Recast-over-the-air-DVR-500GB-75-hours/dp/B01J...Fire stick:
https://www.amazon.com/dp/B08C1W5N87?ie=UTF8&*entries*=0&viewID=&*Version*=1Amazon Device Return policy:
https://www.amazon.com/gp/help/customer/display.html?nodeId=201818950ROKU return policy:
https://support.roku.com/article/360009581054 As with anything the costs rise as you add more options, Amazon and ROKU are about the same for the basic devices, however adding a DVR or premium channels (like GPmoto live events) etc. bring up the cost.