Sunday recovery:

Find a 30 minute yoga flow online and follow it.
We like Yoga with Adrienne on YT. https://buff.ly/3w5e1VN

Go for a walk in nature,
Take a dog or even better find a friend with a dog.
Put on some boots and a back pack.
Find a pub afterwards, get lunch

Why recovery?
Training is designed to cause stress, recovery builds you back better, stronger, fitter.
Sorry to break it to you, but you're not 21 any more and you're not an Olympian.
Train smart & build in recovery or stand by to crash face first into a solid wall of fatigue (somewhere around week 3 usually) then grind to a halt.
Failure to properly recovery = no improvement, just degradation, illness and injury. Then sadness and the bitter taste of regret.

For most of us over 40s, two days of training demands a recovery day. Some people might fair better alternating one day hard, one recovery day. You have to adapt to the reality of your situation rather than following a program that doesn't take your recovery status into account.
We program active recovery which will speed up how fast you recover, but you could just take a day off if you're knackered. Keep eating the protein on your recovery day. Sleep as long as you can.

You can adjust the challenge any workout places on your body by adjusting the intensity right down and limiting the volume..

For recovery, you want to hang out in Zone 1, which is a range of heart rates from  ((220-your age)x 0.5) to ((220-your age)x 0.6). It should feel like a normal – fast walk. Not super taxing.

Photo by v2osk on Unsplash