The way I understand it, is that when making a knot on Shabbos, and you cross the strings over once, and then you tie the 2 Bowes over once, that is not considered a קשר של קיימא and is permitted. I was doing this the other שבת, and I second guessed myself, as that knot with crossing the strings over once, and tying 2 Bowes on top of that seemed very strong and looked like a קשר של קיימא. Is it better to just just cross the strings over, and not knot it, and is it permitted to do one knot.

ב"ה Shalom You may be at ease with tying your shoes, by crossing the strings over once and then tying a bow. This is written explicitly in the Shulchan Aruch- Hilchot Shabbat (שיז:ה ) A קשר של קיימא= a permanent knot is not the only consideration of tying on Shabbat but also what is called מעשה אומן, meaning a professional knot. Because of this factor, The Mishna Berura to the above section in the Shulchan Aruch says that we allow to tie a bow over the laces crossed below on the condition that this bow is untied within 24 hours. If it is not untied, then this know becomes a מעשה אומן which is forbidden on Shabbat. (See שמירת שבת כהלכתה פרק טו:נו, פסקי תשובות סי' שי"ז : יב ,כי בו שבת סי' שי"ז :קא ) Furthermore, the Shemirat Shabbat Kehilchata writes, that if case of need ,one may even make another knot on top of the bow. However, this is also under the condition that it is untied within 24 hours. Therefore, in the case of you tying your shoes as you described there is no problem when the relevant restrictions are applied. All the best