elbendi – “היה הוה ויהיה” of course Hashem can be in the past, present, and future. This specifically means that he was G-d, is G-d, and will always be G-d. I’m absolutely positive Hashem can go back in time or forward in time, but I don’t think that when the author of the 13 Ikarim refered specifically to time travel. When it says
“אֲנִי מַאֲמִין בֶּאֱמוּנָה שְׁלֵמָה שֶׁהַבּוֹרֵא יִתְבָּרַךְ שְׁמוֹ הוּא יָחִיד וְאֵין יְחִידוּת כָּמוֹהוּ בְּשׁוּם פָּנִים וְהוּא לְבַדּוֹ אֱלֺהֵינוּ הָיָה הֹוֶה וְיִהְיֶה”
“וְהוּא לְבַדּוֹ אֱלֺהֵינוּ הָיָה הֹוֶה וְיִהְיֶה” the הָיָה הֹוֶה וְיִהְיֶה was reffering to Hashem being the Aibishter, was, is, & will always be.
So I don’t think we can learn from here that humans can’t travel in time.