Tit 3:5 isn't "problematic" at all. It is as clear, concise and foundational to the gospel as any verse could possibly be. It only becomes "problematic" when someone doesn't like what it states.
The gospel was written solely about Christ - that He came to do the will of the Father
[Heb 10:7 KJV] 7 Then said I, Lo, I come (in the volume of the book it is written of me,) to do thy will, O God.
Here are some more clear, concise and foundational verses.
From Matthew
- Repent (4:17, F)
- Recognize one’s spiritual poverty (5:3, F)
- Be righteous (5:20, W)
- Love your enemies (5:44, W)
- Forgive those who offend you (6:14, 18:35, W)
- Serve God (6:24&33, W)
- Enter the narrow gate (7:13, F)
- Do God’s will (7:21 & 12:50, F&W)
- Hear and act (7:24, F&W)
- Confess Jesus (10:32, W)
- Love Jesus (10:37, F)
- Give life to Jesus (10:39& 16:24-25, F)
- Have no doubt (11:6, F)
- Come to Jesus (11:28, F)
- Learn from Jesus (11:29, W)
- Be for Jesus (12:30, F)
- Understand (13:23, F)
- Be good (5:48 & 13:38,43,49, W)
- Value salvation (13:44-46, F)
- Believe Jesus (16:16& 21:32, F)
- Become humble (18:3-4 & 19:14, W)
- Forgive others (18:35, W)
- Obey the commandments (19:17, W)
- Give to the poor (19:21, W)
- Follow Jesus (19:21&29, F)
- Yield fruit (21:43, W)
- Dress appropriately (22:11-14, cf. RV 16:15, W)
- Love God, neighbor & self (22:37-40, W)
- Hold out until the end (24:13, F)
- Keep awake (24:42 & 25:13, F)
- Be ready (24:44, F&W)
- Be trustworthy and useful (25:21&30, F&W)
- Help Jesus’ brothers (25:34-40, W)
- Be righteous/do right (25:46, F&W)
More from Mark and Luke
35. Accept the kingdom (Mark 10:15, F)
36. Believe the Gospel (Mark 16:16, F)
37. Receive baptism (Mark 16:16, W)
38. Be hated (Luke 6:22-23, W)
39. Lend (Luke 6:35, W)
40. Judge not (Luke 6:37, W)
41. Invite the poor to your party (Luke 14:13-14, W)
42. Use wealth wisely (Luke 16:9, W)
43. Stand firm (Luke 21:19, F)
From John
44. Be born again (3:3&6, F)
45. Come to the light (3:21, F)
46. Drink living water (4:14, F)
47. Heed Jesus (5:24, W)
48. Do right (5:29, W)
49. Work for the food of life (6:27, W)
50. Believe in the one God has sent (F)
51. Partake of the bread of life (6:33-35&51, F)
52. Eat the flesh and drink the blood of X (6:54, F)
53. Dwell within the truth (8:31&35, W)
54. Obey the Son (8:51 & 14:15, F&W)
55. Hate self; serve Jesus (12:25-26, W)
56. Accept Jesus’ words (12:47, F)
57. Follow Jesus’ example (13:15-17, W)
58. Dwell in Jesus and in love (15:5-10, F&W)
59. Heed his command (15:10-12, F)
60. Know God and Jesus Christ (17:3, F)
61. Believe Jesus is Christ/Son (20:31, F)
GRFS per Peter and Paul
From Acts
62. Call on the name of the Lord (Acts 2:21)
63. Repent and be baptized (Acts 2:38, cf. 3:19)
64. Believe in Jesus (Acts 10:43, cf. 13:39&48)
65. Believe in the Lord Jesus (Acts 16:31, cf. 18:8)
66. Repent and turn to God (Acts 26:20)
These only become "problematic" when someone doesn't like what they state.
Would you like some more?