I asked Abdullah b. Abu Aufa (Allah be pleased with him), a Companion of Allah's Messenger (ﷺ), whether Allah's Apostle (ﷺ) had entered the House, while performing 'Umra, He said: NO.
Sahih Muslim Book 15, Hadith 443
← Previous Hadith Ibn Abbas (Allah be pleased with them) reported that Allah's Apostle (ﷺ) entered the Ka'ba, and in it there were six pillars, and he stood near a pillar and made supplication, but did not observe the prayer.

Sahih Muslim Book 15, Hadith 442 Next Hadith → Allah's Messenger may peace be upon him) said to me: Had your people not been unbelievers in the recent past (had they not quite recently accepted Islam), I would have demolished the Ka'ba and would have rebuilt it on the foundation (laid) by Ibrahim; for when the Quraish had built the Ka'ba, they reduced its (area), and I would also have built (a door) in the rear.

Sahih Muslim Book 15, Hadith 444