I found this very helpful explanation on another group chat to which I belong. I thought it might be helpful to post it here for anyone visiting in the next 2 months.
“While there are a few areas with scaffolding up - some of them famous and photogenic - anyone who says "Rome is under construction" likely doesn't understand just how huge Rome is and how many incredible sites there are here to see that are not currently being refurbished.
These are the areas currently affected, with live webcams linked where possible, so you can see what it actually looks like.
Trevi Fountain. Currently emptied of water with a walkway extending over the basin to allow a closer look, and a trough for people's coins while the fountain is empty.
https://www.skylinewebcams.com/en/webcam/italia/lazio/roma/fontana-di-trevi.html
Fontana del Pantheon. The fountain in front of the Pantheon. Currently behind boardings. The obelisk is still visible and the Pantheon itself is not affected.
https://www.skylinewebcams.com/en/webcam/italia/lazio/roma/pantheon.html
The Fountains in Piazza Navona. The Fountain of the Four Rivers and the two fountains at either end of the piazza are undergoing major renovation. The piazza itself is open.
https://www.skylinewebcams.com/en/webcam/italia/lazio/roma/piazza-navona-roma.html
The Arch of Constantine. Triumphal arch next to the Colosseum, currently covered in scaffolding. (Note there are two other large triumphal arches just metres away in the Forum.)
Piazza di San Giovanni in Laterano Some of the piazza in front of the San Giovanni cathedral is being refurbished. This doesn't affect viewing or entering the cathedral, just the ground in front of it.
https://www.skylinewebcams.com/it/webcam/italia/lazio/roma/piazza-san-giovanni.html
Fountain of the Four Lions. The central fountain in Piazza del Popolo has low hoardings around it.
https://www.skylinewebcams.com/en/webcam/italia/lazio/roma/piazza-del-popolo.html
Ponte Sant'Angelo. The famous bridge is having its angels cleaned.
https://www.radiocolonna.it/economia/giubileo-2025-il-punto-ponte-santangelo-incartato-per-il-restauro/
Fontana delle Tartarughe. The turtle fountain in the Jewish Ghetto is also being cleaned.
There are some works in Piazza Pia near Castel Sant'Angelo and Piazza Risorgimento, but they are unlikely to affect sightseers.
Transport
Trams. All tram lines were meant to slowly come back into service from November 4th 2024, but most are still significantly disrupted and subject to replacement buses (navette).
Metro. From Monday to Thursday, Line A closes at 9 pm, with a replacement bus after then until 11.30. On Friday and Saturday nights the last metro each way is at 1.30 am.
Piazza Venezia. The piazza in front of the Altare della Patria (Vittorio Monument) is subject to works on Line C of the metro and the construction of a vast metro station under the piazza.
https://www.skylinewebcams.com/en/webcam/italia/lazio/roma/via-del-corso.html
Via dei Fori Imperiali These are works for Line C of the metro and not related to the Jubilee. This area has been blighted by these for years and will likely be blighted for years to come, until Line C has been connected to the new station at Piazza Venezia.”