Hi Marko --
It's the right weight and diameter. That's good.
This is a very rare coin. I used my favorite CoinArchivesPro database and looked up "Titus Colosseum" and got only 19 matches. That's not very many in a database of 2 million ancient coins.
It is always dangerous to compare ancient coins using side-by-side photos. But, to try to give you the best possible answer, I photoshopped your coin (crudely cut out of your photos) to a known genuine coin. What do you think of the side-by-side comparison?
For one thing, the genuine coin is absolutely amazing. It comes from Numismatica Ars Classica and sold for $464,000 US dollars. CoinQuest thanks Numismatica Ars Classica for use of their coin photo. Their auction write-up appears below.
Trying to compare the two coins, there are marked departures. The two areas I notice are the angle Titus is seated at, and the position of the ball-like helmet below the seat. The size and shape of the shields are different as well.
I looked carefully at the 18 other examples in the database, and none matched the seating angle and position of the helmet. This leads me to believe your coin is a replica.
There is such great potential if your coin is genuine, it is probably worthwhile to have it professionally authenticated. But I would not get my hopes us. This coin is so rare and so valuable, it is a prime target for crooks.
Here is the description from the auction of the genuine coin pictured.
Numismatica Ars Classica > Auction 120 Auction date: 6 October 2020
Lot number: 735
Price realized: 425,000 CHF (Approx. 464,430 USD / 393,883 EUR / 357,983 GBP)
Titus augustus, 79 – 81
Divus Titus. Sestertius 81-82, Æ 26.13 g. Aerial view of the Flavian Amphitheatre (the Colosseum); on l., Meta Sudans and on r., porticoed building. Rev. DIVO AVG T DIVI VE-SP F VESPASIAN Titus seated l. on curule chair, holding branch and roll; around, arms; below, S – C. C 399. BMC 191 note. RIC Domitian 131. CBN Domitian 543. Elkin, NC 2006, p. 217, 8c (this coin). Elkin, Publizing Victory; the frequency and audience of Flavian 'Judaea Capta coins from the Imperial mints, in Israel Numismatic research 14, 2019, fig. 5b (this coin illustrated). Elkin, A Monument to Dynasty and Death, p. 41 (this coin illustrated).
Extremely rare, only the eleventh specimen known of this prestigious and important issue,
which is much rarer with Titus as Divo rather than Emperor. Possibly the finest
Colosseum sestertius in private hands