Ukrainians installed webcams at polling station on previous election, for transparency. When war started, they were still installed. We watched fake referendum in Crimea in real time on site. I personally saw about 3-5 voters per hour on most polling stations, except for stations where Russian tv was: they were full. Moreover, anybody was able to vote, including Russian tourists.
Also, you need to know that Russians are not natives in Crimea. By UN standard, natives are those people, who live in place for 200 years.
Russians expelled native Crimeans from Crimea to Ukraine, to substitute Ukrainians died during genocide, and to Siberia.
They used situation with Crimean Goths as excuse, because Germans used Crimean Goths as translators.
After expelling of natives, Crimean land was used as prize for soviet officers. They had no experience of agriculture in dry climate, so they cut vines and tried to farm potatoes, which caused famine. Also, Crimea was cut from RF, so RF was unable to help.
To fix situation, Crimea was returned back to Ukraine, to rebuild economy, because Ukrainians knows Crimea climate for more than millenia and Crimea was part of Ukraine since breakup of Russian Empire. However, Russians portait this return of Crimea as gift to Ukraine and want to stole it back.