For practicing alone on your guitar the most important thing is that the strings are in pitch relative to each other. A forth apart. Even if they are not tuned in pitch in relation to anything it will good enough for you to practice. But it will also not train your ears.

Because as soon as you try to jam along to your favorite artists, streaming service or if you are one of those people, a CD og even LP you will notice something is wrong if the guitar is out of tune. The same if you play with other muscicians.

You need a reference tone, something that you can tune the other strings after. I would just use any mobile app, or get one of them headstock clip on tuners. As you already are familiar to manual tuning, just tune up one string using the clip on tuner, then do the rest by ear. That way you are also training your ear.