As a Mahayana Buddhist, I don’t differentiate between the attainment of Mahayana and Theravada Buddhist masters.
While the goal of attainment in Theravada Buddhism is widely considered a lesser goal than in Mahayana Buddhism, this is not fundamentally the case:
Samma Sambuddha is a self-enlightened Buddha. That is, a Buddha who realises the Truth (Nibbana) by himself, without the assistance of a teacher…
The last Buddha was of this catergory.
Pacceka Buddha also attains Nibbana without the assistance of a teacher, but unlike theSamma Sambuddha he cannot teach the Dhamma.
Savaka Buddha or Arahat attains Nibbana by following the teachings given by a Samma Sambuddha.
In terms of their Enlightenment, all three Buddhas are identical, but they reach this state by different means (with or without a teacher), and may or may not be able to teach.
If a living person in the Theravada tradition is widely believed to have attained Nirvana, I take that seriously.
If the Buddha taught 84,000 paths to enlightenment, as is widely taught in Mahayana Buddhism, then Theravada Buddhism is included among those paths:
The Basic Points Unifying the Theravāda and the Mahāyāna is an important Buddhist ecumenical statement created in 1967 during the First Congress of the World Buddhist Sangha Council (WBSC), where its founder Secretary-General, the late Venerable Pandita Pimbure Sorata Thera, requested the Ven. Walpola Rahula to present a concise formula for the unification of all the different Buddhist traditions. This text was then unanimously approved by the Council…