Why have REITS performed so badly?

REITs are real estate investment trusts. These are companies that own and operate income producing real estate like apartments, offices, and shopping centers. They are required to distribute the majority of their earnings as dividends rather than plowing that all back into investments. REIT performance is going to vary based on the economic environment, interest rates, and supply and demand for real estate.
Rising interest rates hurt REIT in particular because they borrow money to buy real estate. The other reason high interest rates hurt REITs is that higher yields make bonds more attractive. Bonds are safer investments. In general, a weak economy is bad for real estate.
When the economy is in better shape, and interest rates are lower, REITS will be a more attractive investment. As we see interest rates continue to creep upwards, REITS will continue to be a poor investment.
Apartment REITS would be an attractive if you believe home prices will continue to be elevated and mortgage rates will continue to be unaffordable to the average American.
Industrial REITS own real estate like warehouses and distribution centers. These REITS benefits from strong e-commerce sales. However, I would caution you that we have already see an explosion of warehouse construction and development is slowing down at this point.
There are also data center REITS. This specific sector provides things like space, power, cooling, and security for customer servers.
There is a REIT for most investment strategies, but what all REITs share is a vulnerability to interest rates and the economic environment. However, specific sectors will be more or less sensitive to variables in the economic environment.