Maybe I misunderstood the verse, but Yeshayahu 20:3 teach us that Yeshayahu was a servant and walked naked and barefoot for three years. Why would HaShem allow him to do so? While Adam and Eve had to be clothed because of their nakedness, the nakedness of Noah shouldn’t been seen, and other verses who teach us to dress well before HaShem.
Rashi quotes the Targum Yonatan and says that "naked" doesn't mean literally naked
naked: (עָרוֹם). Jonathan renders: פְּחֵיחַ, with torn and worn out clothing, but not actually naked.
Other commentators mention that it was symbolic or that he was actually only naked for a brief time, in his own house.
Rabbi Yoel Bin Nun has a class on this subject, which I recommend listening to.
He explains that he disagrees with the Rambam's view in this case. Rambam's view has merit in places such as Avraham's meeting with the angels, because of the usage of multiple "vayera" - Avraham sees himself doing things he normally actually does. However, in the context of Yeshayahu, there's no indication that he merely saw himself doing things, but actually did those things. Moreover, an exact date and context for the event is given, which provide an explanation why it was necessary for Yeshayahu to do such a thing.
The background of this strange act by Yeshayahu comes from the political turmoil that was going on at the time:
Some years prior, Tiglat-Pilesser III, king of the Assyrian Empire, began the exile of the Ten Tribes (Melachim 2:15:29), severely weakening the Kingdom of Yisrael. The exile was the Assyrian Empire's punishment for insurgent nations – they executed this punishment all over the Empire. Yisrael were punished because King Pekach had formed an alliance with Retzin, king of Aram, hoping to rebel against the Assyrians. Hoping to strengthen the alliance, they turned to Achaz, king of Yehudah, for assistance. Fearing both the wrath of the Assyrians, Achaz declined. This led the alliance to decide that Achaz and the House of David were not needed, and plotted to overthrown Achaz and set up a puppet-king, someone known only as "ben Tav'al" (Yeshayahu 7:5-6). Yeshayahu, through prophecy, assures Achaz that this won't come to pass. He must only hold out for a year or two, and the danger will pass. Yeshayahu insists that Achaz not turn to the Assyrians for help, and that salvation will come only from trusting Hashem (ibid. 8:13-23).
Achaz, however, is unable to hold out for so long, and surrenders to the Assyrians, begging for help (Melachim 2:16:7-9). The Assyrians agree, and defeat the alliance. While in Assyria, Achaz is drawn to the Assyrian idolatrous religion, and upon his return, executes changes to the Temple, building a new altar based on the one used in Damascus and allows Tiglat-Pilesser to make sacrifices on it (ibid. 10-18) and then proceeded to make sacrifices himself to the gods of Assyria and built bamot all over Yehudah (Divrei Hayamim 2:28:22-25). It is surmised that for his evil deeds, his full name, Yehoachaz, was erased from the Tanach (per the Tiglath-pileser III 47 inscription).
Naturally, Yeshayahu was very angry from what had happened. That had been the consequence of what he had warned against, trusting the Assyrians. During Achaz's son Yechizkiyahu's reign, other regions in the Assyrian Empire were forming alliances to stand up against the Assyrians.
One case is referred to in this chapter, Yeshayahu 20:
"It was the year that the Tartan came to Ashdod—being sent by King Sargon of Assyria—and attacked Ashdod and took it...And now the LORD said, “It is a sign and a portent for Egypt and Nubia. Just as My servant Isaiah has gone naked and barefoot for three years, so shall the king of Assyria drive off the captives of Egypt and the exiles of Nubia, young and old, naked and barefoot and with bared buttocks—to the shame of Egypt!"
This is a reference to a rebellion by the people of Ashdod, who had overthrown the Assyrian puppet-king Achimati and had made king Yamani. Yamani allied himself with the Nubian Pharaohs (of whom Tirhaqah was a descendant of) and that alliance seems to have turned to Yehudah for further assistance. Though this isn't directly mentioned in the Tanach, it's both implied in this chapter and makes sense, considering a different alliance is directly stated to have turned to Yehudah: The Kasdim, at the behest of Berodach Bal'adan, king of Babylon (Melachim 2:20:12-15). When the Babylonians turned to Yechiakiyahu, he actually welcomed them and entertained them, showing them his treasury. It would make sense that Yechizkiyahu equally pondered the Ashdodean-Nubian/Egyptian alliance's requests.
For this reason Yeshayahu removed his clothes and walked barefoot, to make the statement he made in the name of Hashem in the chapter: All such alliances have no hope, all such alliances will fall and be exiled in disgrace, naked and barefoot. Rabbi Bin Nun explains that most likely Yeshayahu didn't walk around that way for three whole years, but did it whenever any group of envoys would come to Yehudah to request the king's assistance. It took three years of doing this, before the alliance fell. Yechizkiyahu had ultimately not assisted them, but it seems that his considering this possibility brought upon the fall of Lachish and other cities in Yehudah and the near-fall of Yerushalayim (Melachim 2:18:13-19:37) – punishment for trusting other world powers instead of Hashem, as Yeshayahu had warned.