@tomaszpl I think it’s awesome you want to make positive changes for yourself.
In regards to always feeling tired you need to get better quality sleep. Just as you would t expect your kids to go right to bed as soon as they hop into bed, you have to treat yourself the same way and try to create a bedtime routine for yourself. Dimming or turning off the lights and lighting candles can help get you ready for bed. Also, limiting screen time and snacking before bed will help too.
As far as training goes you can check things like OfferUp, Let Go, FB Marketplace and others for discounted gym equipment like a barbell, dumbbells, kettle bells or even a sled would be great. If not, yoga, mobility drills or calisthenics would be a great place to start. You can do these between calls, a set number ever other hour or something of the sort. If you’re able to take a walk while you’re on a call that would be great.
Key would be to start small and slowly build upon that. Ask yourself what can you commit to for the rest of your life, is it just one 20 minute walk a day? 5 push ups before bed or first thing in the morning?
Being aware you need to make a change and asking for guidance is the first step. As a dad of 2 young girls I understand the struggles you are/may go through, with persistence and intention you will make awesome changes. Sounds like you have a lot of support here, you got this!