An "old" guy who worked at Home Depot told me awhile back to avoid tools with batteries. I've found that advice pretty useful over the years. They are usually under powered, die at the wrong time, not charged at the right time and are usually hard or darn near impossible to find if needing to be replaced. Cords, while sometimes inconvenient, are the way to go.
Times change, battery operated tools are much better than they used to be. Also, cords can only reach so far unless you want to drag around extension cords. I had a corded electric snow blower for a while and it was a real hassle to hook up the cords and drag it around in the snow. It was no match for my 150+ foot driveway, even with extension cords.
I have an assortment of Dewalt 20V battery operated power tools. Most perform as well, if not better, than the cheap corded tools I used to own. As long as you have extra batteries charged up, a dead battery is a non-issue. Just swap the dead battery for a new one. That's certainly easier than dragging around a cord, or having to wind it up when you're done.
The only time I opt for my corded drill is when I need to use a 2 inch auger bit with my low RPM, high torque Dewalt drill. That thing will rip your arm off if you're not careful.
My EGO string trimmer performs just as well as my old gas powered trimmer. It has a wider cut, handles just as well with thick brush, and there's no gas to mix or fumes to deal with. It's also completely silent when I'm not cutting, moving from one area to another.
I've never owned a leaf blower before, but my EGO blower does everything I need it to. One battery usually lasts long enough for me to clean all the walks and areas around the house. I simply swap batteries if I need to clean more areas up around the driveway or something.
As for finding replacement batteries, you shouldn't have any issues if you stick with major brand names. Also, if you stay with one brand for multiple tools, it allows you to have extra batteries without needing a separate battery for each tool. My Dewalt and EGO batteries are widely available at the local Home Depot, or online from Amazon. However, I have not needed to replace either battery since I bought the tools.
My first Craftsman cordless tools used Nimh rechargeable batteries. They performed well for me too, but I did have several of those batteries die over time. Most new tool batteries are Lithium-Ion now.