An Upper Lower is great for beginners, intermediates and advanced lifters, and is personally what I recommend to anybody getting into powerlifting/strength training.
Research seems to favour a training frequency of 2-3 days per week for optimal hypertrophy, even when volume is equated compared to a “bro split” (Schoenfeld et al., 2016). This is because muscle protein synthesis levels remain elevated 36-48hrs post workout in naturals (Burd et al., 2012). This means a muscle group should be ready to train again after this period, so an upper/lower split works perfectly
This split also allows for the use of daily undulating periodisation (DUP). DUP refers to a daily fluctuation in volume and intensity and is done by changing rep ranges and weights from session to session. DUP has been shown to be superior than Linear periodisation when it comes to increasing strength (Rhea et al., 2002). Undulating rep ranges are also superior to building muscle than fixed ranges (Schoenfeld, 2015). So, if you want to maximise strength gains and muscle growth, following this split, it’s best to do one heavy day in the 3-6 rep range and one lighter day in the 6-10 rep range