So the big issue with scholarship on Beria is he's one of the least accessible (possibly the single least accessible) bolshevik leader to study.
According to Sheila Fitzpatrick in the introduction or preface to On Stalin's Team, when she was allowed access to some of the soviet archives Beria's were off limits. Khrushchev, Stalin, Lenin, Molotov, Yagoda, Yezhov, etc were accessible, Beria's was shut. From what she wrote, his archives werent shut to just her, or to westerners, but to literally everyone.
Fitzpatrick's introduction also notes that most (all?) of the accusations of Beria postdate Khrushchev's secret speech, after which Beria was dead and he and Stalin were used as sin-eaters for the rest of the Soviet government.
She says that bc the archives are shut, what we know of Beria is based pretty much entirely on four groups of sources: 1. pre-1956 official public documents and such ("Comrade Beria is a diligent defender of the USSR"); 2. post-1956 documents ("Beria was a monster and he and Stalin caused every problem"; 3. Beria's son's memoirs ("my dad was a decent guy"; and 4. apocryphal stories which are difficult to date or validate ("Stalin was afraid to leave Beria alone with his daughter"). Besides 2 and 4 (and 4 may well largely be derived from 2) these all paint entirely different pictures, and without archive access theres no real way to prove which is closest to reality.
Fitzpatrick doesnt claim "Beria was innocent" tbc, just notes that there is very little at all that can be said for sure about this question bc of lack of archival access.