One reason why many actors, particularly on a series, wear the same outfit constantly is because it allows for easier use of earlier footage, splicing in previously shot scenes.
Since "Zelensky" is always wearing the same crummy shirt and basic outfit, it's easy to swap footage of him from last year, or use green-screen images from months ago. It helps the media with this propaganda campaign.
One reason why many actors, particularly on a series, wear the same outfit constantly is because it allows for easier use of earlier footage, splicing in previously shot scenes.
Since "Zelensky" is always wearing the same crummy shirt and basic outfit, it's easy to swap footage of him from last year, or use green-screen images from months ago. It helps the media with this propaganda campaign.