Following are some remarks that I made regarding the passage under discussion in a study of the Book of Revelation. I believe they are in general agreement with your understanding of the passage in the OP.
The spiritual condition of the church at Laodicea was worse than that at Sardis. Even the church at Sardis which the Lord spoke of as dead had a few names ... which have not defiled their garments . There was not even this limited praise for those at Laodicea. In their pride filled contentment, the church at Laodicea thought they were spiritually rich but the Lord says thou knowest not that thou art wretched, and miserable, and poor, and blind, and naked.
The fate of the church at Laodicea is apparently sealed. The other churches [Ephesus, Pergamos, Thyatira, and Smyrna] that were reprimanded by the Lord were commanded to repent to avoid judgment. However, there is no such promise to the church at Laodicea as a whole. Rather the Lord is brief: I will spue thee out of my mouth. However, the infinite grace of God is manifest in the exhortation of the Saviour:
18 I counsel thee to buy of me gold tried in the fire, that thou mayest be rich; and white raiment, that thou mayest be clothed, and [that] the shame of thy nakedness do not appear; and anoint thine eyes with eyesalve, that thou mayest see.
19 As many as I love, I rebuke and chasten: be zealous therefore, and repent.
The counsel of the Lord is that the true believers of Laodicea would buy of Him gold tried in the fire and white raiment. This is not to imply that the blessings of grace are for sale; those in the church were universally spoken of as wretched, and miserable, and poor, and blind, and naked. The only thing the believers had of value to the Lord was themselves, the purchase price was be zealous therefore, and repent. That there were true believers at Laodicea is also shown by the Lord’s words: As many as I love, I rebuke and chasten. The chastening if the Lord in the event of sin in the life of the believer is evidence that conversion has occurred. The letter to the Hebrews is very blunt in addressing this problem, as follows:
Hebrews 12:4-8, KJV
4 Ye have not yet resisted unto blood, striving against sin.
5 And ye have forgotten the exhortation which speaketh unto you as unto children, My son, despise not thou the chastening of the Lord, nor faint when thou art rebuked of him:
6 For whom the Lord loveth he chasteneth, and scourgeth every son whom he receiveth.
7 If ye endure chastening, God dealeth with you as with sons; for what son is he whom the father chasteneth not?
8 But if ye be without chastisement, whereof all are partakers, then are ye bastards, and not sons.
In discussing this last part of the letters to the seven churches it is well to keep in mind that the Lord is talking to the Church, those who have been truly redeemed to God. Although the local church may indeed include unregenerate people in its membership, these can in no way be considered a legitimate part of the ekklesia, the ones called out.
The letter to the churches concludes with a promise to the few who believe.
Revelation 3:19-22, KJV
19 As many as I love, I rebuke and chasten: be zealous therefore, and repent.
20 Behold, I stand at the door, and knock: if any man hear my voice, and open the door, I will come in to him, and will sup with him, and he with me.
21 To him that overcometh will I grant to sit with me in my throne, even as I also overcame, and am set down with my Father in his throne.
22 He that hath an ear, let him hear what the Spirit saith unto the churches.
Jesus Christ follows His counsel to the true believers at Laodicea and all churches, As many as I love, I rebuke and chasten, with the promise, Behold, I stand at the door, and knock. This promise[] is only to the regenerate members who constitute the churches. If they repent following chastening, rouse themselves from their false contentment or their sins, and return to their ‘first love’ then He will restore that fellowship that has been broken, I will come in to him, and will sup with him, and he with me. If they do not repent but continue in their sin then the judgment of God will come, even a temporal judgment on the believer [Hebrews 10:29,30].