idiots, lethargic, stupid incompetent people with few tools & some weeks training at roadside truck service stations commonly call themselves mechanics. before you make any serious mistake, take your vehicle to Toyota 3S shop for diagnostics, if that is not very convenient for you locate some shop which can perform compression test over your vehicle.
if at all needed rebuild the engine., car will remain on original engine with no alteration to regn book. and you will be knowing the REAL life after rebuilt with maintenance history.
engine swap is last resort, at your expense for the ease of ...( read line one again )
competent people with automotive repair skills, seldom recommend swaps, they rebuild the engines.