Nope.

Sarawak has always been rich in terms of GDP per capita, consistently in top 3 of all Malaysia states in the past decade, just behind Kuala Lumpur and Labuan, beating Selangor, Penang and Johor [1] that most people perceived as rich and economy driven states.

Their 2022 finances:

Revenues RM 11.9 billion (2022) [2]
Expenses RM 10.6 billion (2022) [3]

Sarawak economy has traditionally heavily depended on natural resource extraction and exports, i.e., oil and gas, timber and palm oil. Their main export partners [4]:

Japan (25.8%)
Peninsular Malaysia (15.7%)
Peoples' Republic of China (11.3%)
Republic of Korea (7.3%)
Republic of China (Taiwan) (7.2%)

They have their control long ago to enrich themselves and just that the peasants willingly fooled themselves to believe they have not been in control and grateful they have the second coming of Jesus to resurrect them from independence.

[1] https://en.wikipedia.org/wiki/List_of_Malaysian_states_by_GDP

[2] https://www.businesstoday.com.my/2023/02/02/abang-johari-sarawak-records-rm11-9-billion-revenue-for-2022/

[3] https://web.archive.org/web/20220702022625/https://www.newsarawaktribune.com.my/sarawak-approves-rm10-646-bln-budget-for-2022/

[4] https://web.archive.org/web/20210607170429/https://www.theborneopost.com/2019/09/29/enhancing-access-to-sarawaks-trade/